The urethane casting build process involves first creating a master pattern — essentially a replica (often 3D printed) of the final part. The pattern is then fully encased in liquid silicone and allowed to cure. The mold is cut into halves and the pattern removed. From there, the process can be repeated using the proper urethane casting resin.

Polyurethane casting materials are capable of providing performance characteristics comparable — if not superior — to the thermoplastics used in injection molding. However, as with other production methods, the process of casting high-quality parts that meet all performance requirements also requires that product teams follow design for manufacturability (DFM) best practices. Here are some of the most important guidelines for product teams to keep in mind:

Tolerances

Some degree of variation is inevitable in manufacturing (though teams should endeavor to account for as many of the variables as possible), and tolerances are the acceptable amount of dimensional variation between individual units. Cast urethane tolerances are typically around  ± 0.015” or ± 0.003 per inch, whichever is greater. Tighter tolerances may be offered on a case-by-case basis.

In general, a shrinkage rate of +0.15% is typical. This is caused by the thermal expansion of the urethane casting material and how the flexible silicone mold warms in response.

Additionally, it’s important to note that while urethane cast parts take well to post-processing (though additional processes, such as polishing or custom finishing, can quickly drive up production costs), some design features like sharp corners or lettering may experience slight rounding in the cooling process, impacting the definition of finer details. That said, it is possible to add a finish to the master pattern that mimics an SPI finish or texture. You can also paint urethane cast parts to match Pantone colors, and certain color and pigments can be added directly to the casting materials, as well.

Wall Thickness

Parts produced with urethane casting should have a minimum wall thickness of 0.040” (1mm), though walls as thin as 0.020” (0.5mm) can be achieved for some small components. Larger parts generally require thicker walls in order to ensure the piece’s structural integrity.

Urethane casting does allow for parts with varying wall thicknesses or irregular geometries, but designing parts as such should be done only when strictly necessary. Maintaining a consistent thickness helps to minimize the potential for improper shrinkage and deformation during the curing process.

Undercuts and Draft

While undercuts can quickly complicate injection molding design, the flexible nature of the silicone molds used in urethane casting typically allows for parts to be removed easily and without damage.

The same is true for draft angles: they are a necessity for ejecting pieces from metal molds, but less essential for urethane-cast parts. That said, incorporating 3-5 degrees of draft into part design can significantly reduce strain on your mold and extend its life cycle.

Ribs

Ribs add stability and strength, but it’s important to ensure that they are oriented so as to maximize the bending stiffness of the walls they support. As a general rule of thumb, the rib’s height should be no more than three times its width, and the width of the rib where it meets the part wall should be between 40-60% of the wall thickness. Lastly, to maximize the strength of the rib, all interior corners should have a fillet radius of at least 25% of the part’s wall thickness.

Bosses

Bosses allow secure mating parts to be attached through the use of screws, pins, and other fasteners. As with ribs, the base radius should be about 25% of the part’s wall thickness, which has the added benefit in this case of helping to prevent the fastener from burning when it’s set into the boss.

Interior boss corners should use a 0.060” (1.5mm) fillet radius to minimize thickness and reduce the likelihood of sinks developing. Ensuring that bosses are no more than 60% of the nominal wall thickness also helps to minimize shrinkage.

Leverage the Benefits of Urethane Casting Today

The advantages of urethane casting — short lead times, low cost, and design and material flexibility, to name a few — only truly pay off if you adhere to design and manufacturing best practices. This means paying attention to variables like urethane casting material properties, general tolerances for rubber parts, and everything in between — which quickly becomes complicated without the assistance of an experienced manufacturing partner.

With our agile approach, we’re able to significantly shorten lead times and increase operational efficiency for product teams of all shapes and sizes. And at SyBridge, our business isn’t just based on manufacturing superior parts — we also work tirelessly to make sure that our production processes are as efficient as possible, even if that means using a combination of techniques to get the job done. Contact us today to learn more.

The post Critical Design Guidelines for Urethane Casting appeared first on SyBridge Technologies.

Multi Jet Fusion enables the efficient production of end-use nylon parts using additive technologies. Here’s a checklist for design teams.

Introduction

What is Multi Jet Fusion?

Multi Jet Fusion (MJF) is an industrial form of 3D printing that can be used to produce functional nylon prototypes to higher volume production parts with exceptional design freedom and mechanical properties. The MJF process works by using inkjet nozzles to selectively distribute fusing and detailing agents across a bed layered with nylon powder. Unlike selective laser sintering, which uses lasers to fuse the powder into solid material, the MJF printer uses a continuous sweeping motion to distribute agents and apply heat across the print bed layer by layer until the part is finished, MJF can produce high-quality parts at high speeds.

This manufacturing process also does not require support structures to produce parts, making it possible to create complex geometries like internal channels or co-printed assemblies. MJF parts have mechanical properties comparable to injection-molded ones, but without the need for expensive tooling.

Designing for manufacturability will go a long way in ensuring optimal part quality and yield, minimizing post-processing needs, and driving cost reductions. Here’s a quick checklist to help your team ensure that you’re following MJF design best practices.

1. Is MJF a suitable process for my project?

Before diving into design changes, it is important to ensure that the MJF process will meet all product requirements. Here are a few questions to ask yourself:

Do any of the material offerings meet my product requirements?

While MJF has many strengths, it has a limited list of approved materials. PA12 and its glass bead counterpart are fairly versatile for rigid plastic applications. TPU, a flexible polyamide, can find use where an elastomeric material is required. If the available materials do not meet a specific requirement, you may need to consider a different process.

Does my part fit in the build volume?

One key limiting factor is the machine’s build volume, which is 380 x 380 x 284mm for the Jet Fusion 4200. In some cases, large parts can be printed as smaller subcomponents and assembled using adhesive or mechanical joints. In this case, design features such as dovetail joints may facilitate alignment and adhesion.

Do I have any tight tolerances I need to hit?

While the gap between additive and injection molding tolerances is narrowing, it is important to make sure that MJF’s tolerances are sufficient within the context of your assembly.

2. Are there areas where I can use less material?

In most cases, MJF defects are caused by thermal gradients that develop during the build. If the material cools unevenly, the piece may warp or develop sinks. Parts that are long and thin, have abrupt changes in cross-sections, or have thin curved surfaces are especially prone to shrink-induced warp.

Removing material from part designs wherever possible through the use of pockets, shelling, lattices, and topology optimization is key to mitigating and preventing these defects. Avoiding large changes in cross-sections is another way to limit warp. Ensure that chamfers and fillets are incorporated where needed throughout the part design to make the transitions between different features more gradual.

3. Are my features above the minimum threshold size?

In general, the wall thickness of MJF-printed parts should be a minimum of 1.5mm. Small design features should also be no smaller than 1.5mm, though some features such as slits, embossing, engraving, or the diameters of holes and shafts can be as small as 0.5mm. For embossed or debossed text, the font should be no smaller than 6pt (approximately 2mm) and should be a minimum of 0.3mm deep.

If a part includes screw threads, they should be M6 or larger. Where smaller, more precise, or more durable threads are needed, consider using threaded inserts. Beyond feature resolution, you should also consider how small, slender features might break off in post-processing.

4. Have I taken assembly tolerances into account?

Even with the greater geometric flexibility provided by the MJF process, some applications may still require a part to be assembled from multiple components. In general, mating faces should have 0.4 – 0.6mm of clearance to ensure that the components can properly fit.

If your project involves co-printing assemblies, the components printed together should have at least 0.5mm of clearance, but may require more, particularly when there are thick cross sections or there is a significant contact surface area.

5. Is my part design optimized for post-processing?

If your part requires post-processing, there are a few things to double-check in your design to help make secondary operations more effective.

1. Ensure that there are no unvented or trapped volumes in the design.
2. Avoid blind holes whenever possible — these are hard to clean, which can quickly drive up costs.
3. Add fillets to corners where the powder can cake and become difficult to remove through standard tumbling and bead blasting.

6. Have I seized every opportunity to lower part costs?

Besides improving part quality, intelligent DFM changes can drive cost savings. Lightweighting your part, for example, reduces the risk of defects and lowers the material cost per part. The other main consideration when designing for MJF and cost is optimizing nestability in a build. Adding draft or altering the position of printed assemblies may increase the number of parts that can fit per build and distribute fixed costs over more parts, lowering the overall part cost.

In addition to optimizing designs for manufacturability, additional factors to consider include your part’s cosmetics, surface finish, and ease of storage and transportation. MJF parts are naturally grey, but can be dyed black easily. If painting, priming, or other processes are not essential to the part’s function, they can be foregone to reduce expenses. Most MJF-printed parts will have a 125-250 microinches RA finish — if a smoother surface is needed, the part can undergo a variety of surface treatments, including sanding, tumbling, or vapor smoothing. Texturing can be an effective design technique to improve part aesthetics without additional post-processing.

Getting Started With a DFM Expert

Adhering to DFM principles is key to the success of manufacturing processes for a number of reasons. It helps to keep your operating expenses as low as possible, allows you to detect and address design issues early, and improves your overall part quality. This checklist is a valuable resource for making sure your MJF parts are optimized and refined before production begins.

The added advantage of partnering with SyBridge is that your team gains access to the latest in digital design technologies and expert advice. Our team is standing by to help guide each project from design and prototyping through to fulfillment, ensuring that you receive superior-quality parts on time and at the right price. Contact us today to get started.

The post HP Multi Jet Fusion Design Guidelines appeared first on SyBridge Technologies.

by Charlie Wood, Ph.D.
VP of Innovation, Research & Development

As a part of the SyBridge team, I’ve witnessed the remarkable evolution of design and engineering tools over the past decade. These digital advancements have revolutionized our approach to manufacturing, allowing for more data-driven processes and insights. But it can be difficult to know where to start, or even to understand where there are opportunities to implement.

At the heart of our approach lies the concept of the “Digital Thread,” a framework that interconnects data across the entire lifecycle. This concept enables us to leverage the wealth of design and operational data across our data lake that is generated in the manufacturing process, from CAD designs to inspection results. While the industry is still moving towards seamless integration, we’ve made significant strides in creating workflows that prioritize data-driven decision-making.

Streamlining Injection Mold Design Workflows

One key area where data is contributing to efficiencies within manufacturing is that of injection mold tooling design. By utilizing virtual component libraries for mold designs, we’ve been able to streamline the complex process of coordinating and collaborating on intricate assemblies for mold making. In these libraries, we have standard blocks, system approaches and components stored in a way that allows us to quickly identify and digitally pull components. This approach offers lots of flexibility when it comes to customer requests and needs, all while keeping standard practices built right into our tools. Over the course of many years, we’ve built software-driven processes to design new builds based off of these standard components, allowing us to quickly handle new requests from customers and build a learning feedback loop to avoid costly mistakes.

Additionally, through the use of parametric component libraries, we’ve been able to significantly reduce design complexity and incorporate our own manufacturing intelligence into these components, allowing us to directly check for design issues and integrate manufacturing information into CAD files. This process creates a flow of information from the conceptual stage of the design through manufacturing and approval, extending our Digital Thread from end to end. This information flow can also go backwards, tying quoting, estimation assumptions and specifications directly to tool designs. These advancements in our design approach have not only made the job of a tool designer a bit easier, but have improved quality by creating
more explicit feedback loops in our design processes.

Innovations in Conformal Cooling

As many know, 3D printing has unlocked incredible design freedom for manufacturing engineers around the world. However, what can be overlooked is how impactful it has been for system designers, like toolmakers, who can utilize that design freedom and low cost of complexity to create components that radically improve performance. In the case of toolmaking, 3D printing has unlocked new cooling channel designs simply not possible before.

Although increasing numbers of toolmakers are using these advanced manufacturing techniques today, the new design space is so complex it can be hard to probe. In the past, conformal cooling channels were fairly straight, in-plane paths driven by tool access limitations in machining. With metal 3D printing, the limits are far less restrictive and allow designers to pursue more creative and complicated structures.

Using advanced data-driven methods with virtual design and testing capabilities, we’ve been able to uncover non-obvious opportunity areas in the design space. Through these novel design and
manufacturing workflows, we’re optimizing cooling performance and achieving remarkable improvements in tool performance as measured through cycle time. Through our approach, we’re seeing cycle time reductions as high as 50%. These successes have inspired us to further integrate and enhance these workflows, driving continued innovation.

AI Tools for Manufacturing

The Fast Radius Portal’s AI-powered DFM checks

Looking ahead, we’re enthusiastic about the possibilities that emerging technologies like machine learning (ML) and artificial intelligence (AI) offer. These novel data modeling approaches have shown incredible potential, and the pace of technological advancement is rapidly accelerating. We’ve been able to use ML models to build data models faster than through simple bottom-up logic, particularly for complex problems that contain many correlating factors.

The critical ingredient in implementing AI for manufacturing are large data sets that provide a source of truth for model training and validation. By leveraging our existing datasets, we aim to predict defects, optimize designs in real-time and ultimately revolutionize quality control processes. These technologies are not a distant vision; they’re an integral part of our current digital platform, with features like instant quoting and DFM checks based on captured manufacturing data. And this is just the beginning of what’s possible.

Unlocking Manufacturing Innovation via the Digital Thread

Our journey in harnessing digital workflows for injection molding design has seen remarkable progress and tangible results. The end-to-end integration of data into the Digital Thread, combined with the power of ML and AI, holds the key to unlocking even greater innovation. As we continue to push boundaries and explore new frontiers, we’re excited about the advancements at the interface between the physical and digital worlds.

Are you ready to harness the power of the Digital Thread for your organization? Contact us today to get started.

The post The Digital Thread: End-to-End Data-Driven Manufacturing appeared first on SyBridge Technologies.

Our software automatically checks your part files for issues that will make them difficult to manufacture. 

Additionally, SyBridge On-Demand also tracks parts from design to manufacturing to fulfillment, so you can see how different design elements contribute to a part’s success or failure. We feed that information back into the system to continually improve our models, resulting in automated design checks that get smarter every time you use them.

A Data-Driven Approach to Design

When you upload your design, it’s automatically checked for a variety of issues that can impact manufacturability, function and overall quality. These checks help you identify potential problems early and ensure clear communication about what you can expect from your manufactured parts. 

A red X indicator means there’s a critical manufacturability issue that you should address before manufacturing your parts. Though you can still proceed to manufacture parts with such issues, they may not turn out as you intended or could have defects.

An orange exclamation point indicator means that there are elements in your design that might cause issues. Our team sees these checks too, so they’ll let you know if they anticipate any major issues.

If you’re not sure how to fix an issue, you can submit your part for a manual quote so our team can take a look.

Take a look at the chart below for a brief overview of the DFM checks we perform and how any issues may impact your final parts.

* Included with Fast Radius Pro subscription

Get Design Feedback in an Instant

To get started, simply upload your design file and choose your manufacturing process and material.

Checks are listed on the right side of the screen. Each check expands to show a more detailed description of the issue. Clicking on a check will highlight that specific issue on your part visualization. If you need help understanding any of the checks, you can contact our team of experts right from within the Fast Radius Portal.

Once your part passes the necessary checks, you can place your order and checkout. Alternatively, you can also submit your design for a manual quote to start a conversation with our experts. Contact us today to get started.

The post Automated Design for Manufacturability (DFM) Checks appeared first on SyBridge Technologies.

In the manufacturing business, more money put into production generally means less profit or higher prices for customers. But careful planning and informed decision making about your design will help save time and money during the CNC machining process.

CNC machining costs can be divided into two main buckets: non-recurring costs and piece costs. Non-recurring costs refer to all of the upfront costs required to get any production run (large or small) off the ground; these costs are amortized over the production quantity. Piece costs are expenses associated with each individual part, and scale with quantity. The bottom line cost to manufacture a single part, taking into account all cost buckets, is often referred to as the fully burdened part cost.

To put this in mathematical terms: 

Fully Burdened Part Cost = Non Recurring Costs / Quantity + Piece Costs

Non recurring costs include:

• Part design 
• Planning (manufacturing process, inspection, etc.)
• CAM programming
• CMM programming 
• Workholding, fixtures, gauges, and tooling identification and sourcing

Piece costs include:

• Machine time
• Labor time (loading and unloading parts)
• Consumable tooling
• Raw material
• Cleaning, deburring, and finishing 
• Manual inspection

Following the equation above, in lower volume runs, non-recurring costs are amortized over fewer parts, which means the expense is higher per part. For example, if the non-recurring costs for a job are $5,000, and the production quantity is 100 parts, then each part will have a burden of $50 for non-recurring expenses. On the other hand, if that same job is ordered for a quantity of 200 parts, this would result in a non-recurring burden of just $25 per part, a potentially significant cost delta. The good news is that you can minimize CNC machining costs for shorter production runs by optimizing your part designs.

Design tips for short production runs

To maximize your time and budget, try these design tips for short production runs:

Use standardized, simple designs

Keep your design as simple and standardized as possible. Overly complicated part designs can require multiple manual rotations and repositions, more expensive CNC systems, or specialized tools. With this in mind, it may be worthwhile to break up a complex piece into simpler components that can be assembled later.

You’ll also want to:

• Design standard-sized holes: The deeper the hole, the more complex the metal chip evacuation process, and the more expensive your part. Try to make each hole’s depth no more than five to six times the drill’s diameter to ensure your machinist can quickly evacuate the metal chips. Also, make sure to use standard drill sizes when designing your holes or you may end up needing to purchase a custom tool, which can drive up costs and overall production time further.
• Use standard threads: As with drill sizes, using standard thread depths and diameters can save time and money. In practice, this means simply using an existing thread class instead of creating a custom thread via CNC machining or 3D printing. Try to use the H2 thread tolerance, since H3 is tighter and more expensive to create. Also, it’s best to keep your thread depth no deeper than required by your part’s functional and structural specifications.
• Design with standard stock sizes in mind: You can also cut costs and machine times by designing your parts to align with standard stock sizes. Instead of ordering a larger piece of material only to have to machine it down, your machinist will be able to buy a standard stock piece and then make few (if any) changes before starting on your part. Beyond choosing standard stock sizes, it’s also a good idea to allow a large enough tolerance so that the outside of the part does not need to be machined.
• Use loose tolerances: Tight tolerances can require specialized manufacturing processes or secondary operations, and can increase set-up, machining, and inspection time and cost. With that in mind, your part’s tolerances should only be as tight as required by functional and structural constraints.

Avoid thin walls, tall walls, and narrow pockets

CNC machining can be a delicate and time-intensive operation, especially if you have thin walls, tall walls, or narrow pockets.

Since they can increase the risk of cutter deflection, deformation, compromised surface finishes, and part failure, and make it difficult to meet specified tolerances, thin walls are generally less stable and more expensive to machine. Beyond those considerations, your machinist may need to take numerous passes over a part to create a thin wall without accidentally fracturing or snapping it with excessive vibrations, which will, of course, further drive up machining times and costs.

There are options for addressing the increased machining times, higher production costs, and fracture risks associated with thin walls. For example, if you have a metal part, try to design walls that are at least 0.8 mm thick. For plastic parts, try to aim for walls at least 1.5 mm thick. Similarly, you’ll want to avoid including tall walls, deep cavities, and narrow pockets in your part, since these features require longer cutting tools and the removal of more waste material. Like the problems associated with thin walls, these issues can lead to increased cutting tool deflection, chatter, inaccuracies, reduced tool life, and sub-par surface finishes, all of which drive up the final part cost.

Avoid unnecessary text or finishing processes

Adding text to your part will enable you to clearly number components, include a description, or apply a company logo. While machined text looks aesthetically pleasing, and can be functionally useful, it’s an expensive and time-consuming process since you’ll need to trace each character with a small ball end mill or engraving tool. Unfortunately, including raised text on a part is even slower and costlier since even more material will need to be milled away from the part to achieve the effect.

As an alternative to machining, if your part requires text, lettering, or a logo, you may be able to save time and money with a post-production surface finishing method. For example, silk screening, laser marking, rubber ink stamping, and painting will all enable you to add text to your parts faster than direct engraving. Of course, given that adding any CNC finishing process will increase your parts’ turnaround time and overall costs, it’s best to avoid text and other non-critical finishing processes whenever possible.

Choose the proper material

Material selection is important in both long and short production runs since using the wrong metal or plastic for your parts can drastically increase project costs. Some materials are more difficult to machine than others, which means longer turnaround times and higher machining costs. Even if two materials are equally machinable, the chances are that one will be more expensive than the other.

For example, while titanium is ideal for aerospace applications, it’s expensive and difficult to machine. On the other hand, softer, less costly metals, such as aluminum, are easier to machine and strong enough for everything from airplane parts to architectural components. Similarly, if you want to create a plastic part but don’t require the strength or high heat resistance of polyetheretherketone (PEEK), you can save money by using acrylonitrile butadiene styrene (ABS) or another high-performance engineering thermoplastic.

To put it simply, if you don’t really need the properties of an expensive and/or rare material, you should use a less expensive and/or more common material. As an added benefit, using a more readily available material also likely means a reduction in your parts’ overall lead time. It’s worth applying this mentality during the prototyping phase, too; for example, if you only need to create a proof-of-concept model, you should use the least expensive plastic that will still demonstrate the feasibility of your idea.

Additive manufacturing as an alternative for short production runs

While designing with CNC machining lead times in mind can help reduce turnaround and cut costs, depending on your material requirements and the size of your run, additive manufacturing might represent a better option

In contrast to CNC machining, which is a subtractive process that involves cutting away material to shape a final product, the additive manufacturing process builds parts layer by layer. Additive manufacturing is typically far less labor-intensive than CNC machining, sometimes only requiring limited mid-production repositioning and limited post-processing to enhance a part’s functionality, or to achieve a desired finish. Like CNC machining, additive manufacturing can be used to make metal parts, but plastic additive manufacturing is far more common. In fact, many of the plastics used in additive manufacturing are mechanically equivalent to those used in injection molding. 

Generally, additive manufacturing is a better choice for extremely low-volume production runs or for projects in which finished parts or prototypes must be delivered fast, and where tolerance requirements are not tight. By contrast, CNC machining is more appropriate for low-volume production runs with part quantities in the higher double digits or low hundreds, or in projects that have high tolerance requirements.

Working with an experienced manufacturing partner

Each of our design tips for short production runs can help you ensure that your production process is as smooth, cost-efficient, and fast as possible. However, there’s a lot to keep track of when optimizing parts for low-volume production, so working with a trusted manufacturing partner is also a valuable opportunity to take some of the weight off your shoulders.

From design through fulfillment, when you work with SyBridge, our team of experienced engineers will provide you with the support you need to make your project possible. Our cloud-based tools are designed to help you pinpoint design flaws, determine optimal order quantities, and find the right material for your part’s specific application. Simply create an account and upload your part files. We can generate instant quotes for both additive manufacturing and CNC machining projects, which means you can get started making your new parts and products today. Contact us today.

The post Design Tips for Low-Volume CNC Machining Production Runs appeared first on SyBridge Technologies.

Injection molding is a popular and versatile manufacturing process that enables companies to produce high-volume production runs for a relatively low cost-per-part without sacrificing quality. It’s highly repeatable and capable of producing strong components that meet strict mechanical and dimensional requirements.

When companies need to produce a plastic part with thin walls, such as certain car parts or cell phone cases, they can turn to thin wall injection molding. However, you’ll need to be particularly careful when designing products with thin walls, as thin wall injection molding introduces new challenges. In this article, we’ll go over the basics of thin wall injection molding, its common applications, and some injection molding design tips so you can start your journey off on the right foot.

What is thin wall injection molding?

Thin wall injection molding is a specialized form of injection molding that enables manufacturers to create thinner and lighter parts without sacrificing structural integrity. By opting for thin wall injection molding over traditional injection molding, companies can save material, boost productivity, achieve a lower cost-per-part, and reduce shipping-related fuel usage and carbon emissions.

Since thin wall plastic parts have less material to cool, cycle times are much faster, reducing delivery lead times. In fact, a significant reduction in wall thickness can sometimes cut cycle times in half, helping companies get products in customers’ hands faster and saving on operating costs. Plus, since thinner walls mean less plastic, companies can save money when it comes to materials and, in the case of containers and packaging, leave more empty space for the product.

However, thin wall injection molding comes with a few challenges. For one, the injection process is more complicated. You need higher pressure and faster molding speeds to fill all the thin cavities with molten material, avoid freezing off, and ensure the part comes out as intended. For example, while a component with standard walls can be filled in two seconds, that same part with 25% thinner walls may need to be filled in just one second. Additionally, you may need to take extra steps and carefully design gates to ease part ejection.

Common uses of thin wall injection molding in manufacturing

Manufacturers often turn to thin wall injection molding when it comes to plastic packaging, as it can be used to create everything from food-safe packaging to medical device packaging. Other common uses of thin wall injection molding include cell phone components, plastic lids and containers, electronic housings, syringes, and medical device components. Even the automotive, construction, appliance, and aerospace industries use thin wall injection molding for parts and component assemblies.

Thin wall injection molding design tips and tricks

Thin walls often lead to material flow problems, which can cause unformed areas. Other common issues associated with thin walls include uneven cooling, warp, cracks, cosmetic texture inconsistencies, and weak knit lines or fracture points.

To avoid these problems and create the best possible part:

Pay attention to your material

Material choice is always important for injection molding, but it’s essential when creating parts with thin walls. Some materials, such as polycarbonate (PC), are sticky, making filling molds with thin walls difficult. However, certain thermoplastics will flow more easily through narrow sections of a mold, such as high-density polyethylene (HDPE), low-density polyethylene (LDPE), nylon (PA), and polypropylene (PP). Liquid silicone rubber (LSR) also fills easily, though it may increase the risk of flash along your mold’s parting lines.

There’s no one-size-fits-all material for thin wall injection molding, so consider your part’s geometry and application needs when comparing materials. Also, try to choose a material that won’t accelerate mold wear when injected at high speeds.

Consider your mold material

In addition to thinking about your product’s material, you’ll need to carefully consider your mold material. While P20 steel is often used in conventional injection molding applications, it may not be strong enough to withstand the high pressures, wear, and erosion associated with injection molding parts with thin walls. Instead, you’ll need a more robust material, such as 718, H-13, D-2, or another tough steel.

It’s important to note that you may end up paying 30%-40% more for a tool made of a robust material compared to one made of P20. However, that additional cost can be easily offset by the tool’s increased performance and longevity.

Have uniform wall thickness

If possible, ensure your design has uniform wall thickness throughout. This will allow for even cooling and help prevent warping, sink marks, flow lines, and short shots. For best results, keep your wall thickness a minimum of 0.9mm (0.0354”) or greater.

Add ribs or gussets

You can include ribs in your part design if you need to strengthen your part or increase its rigidity. While ribs are generally half the thickness of the wall they support, your ribs may be as thick as your wall if your wall is less than 1mm thick. However, sink marks and read through may be visible where the rib intersects the wall.

Incorrectly designed ribs can result in warp, sink marks, voids, and breakage, causing more trouble than they’re worth. To avoid these problems, design ribs to be 60% of wall thickness or less, keep base radii small, space ribs apart by three times the wall thickness, and include 1°of draft or greater.

If you want to reinforce your thin rib wall without making your ribs thicker, add gussets (or cross-support ribs) and follow the same set of guidelines.

Include radii

Sharp corners are never good in injection molding, as they can cause parts to stick to the tool during the ejection process. They also require more pressure to fill and can result in voids if there isn’t sufficient pressure, so it’s important to include radii and round out internal and external corners and edges. Since the mold cavity is incredibly narrow in thin wall plastic injection molding, avoiding sharp corners and edges is even more critical to ensure a smooth flow of material and a clean ejection.

Pay attention to the temperature

Mold temperature is key to the injection molding process and can drastically impact how the final product looks and feels. A warmer mold allows the injected plastic to flow more easily, resulting in better surface quality.

When it comes to cooling, place non-looping cooling lines directly in your core and cavity blocks to keep your mold’s surface temperature as consistent as possible. Additionally, try to increase the amount of coolant flow through your tool, rather than decreasing coolant temperature, and ensure the temperature difference between your delivery coolant and return coolant is less than 10° F.

Design gates with care

Since thin wall injection molding involves higher injection speeds and pressures, gates should be larger than the part’s walls to help minimize gate wear and material shear. This will also help prevent or eliminate freeze-off from occurring before packing is achieved. If your gate connects to a thin wall with a pinpoint, hot-drop, or sprue, you can reduce stress at the gate and improve the filling process by including a gate well.

You may also want to increase the draft angles of reinforcing ribs, edges, and bosses, as thin-walled plastic parts experience minimal shrinkage.

Creating thin-walled parts with SyBridge

Thin wall injection molding not only helps companies reduce part weight and material consumption, but it can also help reduce costs and cycle times. However, you’ll need to follow these tips and tricks to avoid material flow problems, uneven cooling, and other problems.

An experienced manufacturing partner like SyBridge can help you through the injection molding process, from design to production. When you work with us, we can help you design injection mold tooling and manufacture quality parts quickly and cost-effectively. Plus, by uploading your part file to our website, your design will go through instant DFM analysis to identify potential manufacturability issues. Contact us today to get started on your next injection molding project.

The post Thin Wall Injection Molding Design Tips and Tricks appeared first on SyBridge Technologies.

If you need to connect two pieces of a product or part, you don’t need to rely on an adhesive or add metal hinges or other fasteners during post-production. Instead, you can use snap-fit joints. Simply put, snap-fit joints connect two pieces using small protrusions (or joints) such as beads, studs, or hooks that fit into matching depressions on the mating part.

Snap-fit joints can be made with injection molding; however, injection mold tooling for snap-fit joints can be expensive and complex because of the need for undercuts. Additive manufacturing, or 3D printing, has opened up greater design flexibility for unique or custom snap-fit features, creating new opportunities for manufacturing parts with snap-fit joints in their designs.

Whether you use additive manufacturing or injection molding to create your snap-fit joints, you’ll need to pay careful attention during design to ensure the resulting joint is both functional and reliable. You’ll also want to choose a suitable material and snap-fit joint type.

What is a snap-fit joint and what makes it so useful?

Incorporating snap-fit joints into your designs makes assembling parts much simpler than relying on a more traditional style of joint that would normally be attached post-production because when using snap-fits, the joint is added during production. Snap-fit joints are especially useful in injection molding and additive manufacturing because of the flexibility they provide during the assembly and disassembly processes. There’s also the benefit of pliability, as snap-fit joints are typically made of plastics that allow for more flexibility, even under stress, than other materials.

There are three main types of snap-fit joints:

Cantilever – This is one of the most common types of snap-fit joints. Cantilever snap-fit joints are composed of very simple geometric shapes, making them easy to design and also making it simple to calculate the amount of strain they will be able to handle once manufactured.

Annular – Annular snap-fit joints are common for designs that involve elliptic or circular parts, such as pen caps or lids for containers. The main property of annular snap-fit joints is the compression and stretching of their circumference.

Torsion – Torsion joints work by snapping into place and are both economical and versatile. Because torsion snap-fit joints deflect by twisting a beam, these joints are ideal for creating easily separable connections.

Best practices for designing a snap-fit joint

One of the most important elements of designing snap-fit joints is relieving stress and strain on the joints to promote durability and increase the functionality of a design. To do that, two important design aspects to consider are the taper and width.

Taper – To more evenly distribute stress on the joints and materials of a snap-fit, it’s helpful to taper the cross-section of a cantilever beam over its length. Additionally, tapering a cantilever reduces the amount of material used in the manufacturing process.

Width – While it’s always recommended that clips of a snap-fit joint be at least 5 mm, increasing the width of the clip is sometimes beneficial for adding strength to a snap-fit design. Just make sure to test the stiffness of the clip thoroughly, as increasing width is sometimes a trial-and-error process.

Commonly used materials for snap-fit joints

While there are several processes to choose from when making parts with additive manufacturing, each requires different considerations when selecting the best material to produce a snap-fit joint. Here are the most commonly used materials for creating snap-fit joints using 3D printing technologies.

1. FDM – While FDM is a cost-effective additive manufacturing solution, it requires using stronger materials that are stress resistant when making snap-fit joints, such as ABS, nylon, and TPU. If you opt for a less stress-resistant material, the snap-fit joint will likely break rather than bend.
2. SLA – Not all resins are alike, so when using SLA to make snap-fit joints, choosing the right material, such as Tough 1500, can dramatically improve durability.
3. MJF – MJF incorporates high-strength tensile nylon or glass-filled nylon to produce complex, intricate designs, with PA 12 being the go-to material for snap-fit joints.
4. DLS – Carbon Digital Light Synthesis™ is an industrial 3D printing technology that helps users produce isotropic parts. Parts made with DLS can be rigid or flexible depending on the user’s preferences, with RPU 70 being the recommended resin for snap-fit joints.

Snap-fit joints are an excellent choice for designing durable products that are also cost-effective. However, designing snap-fit joints requires an understanding of not just the processes by which to relieve stress on the joints but also the correct material for the 3D printing process. SyBridge can support your 3D printing needs from prototype to final product, including incorporating snap-fit joints into your parts. Contact us today to get started.

The post Tips for Designing Snap-Fit Joints appeared first on SyBridge Technologies.

Sustainability is becoming increasingly important for businesses and consumers alike. Not only can businesses capitalize on opportunities for tax credits and more stable energy prices, but in the long run, companies that commit to sustainability will see greater success with consumers as individuals seek environmentally friendly product offerings.

From the energy and material used in production to the carbon emissions from transportation, there are opportunities across the manufacturing process for businesses to improve their environmental impact. One simple place to start is with product design. Simple changes — like lightweighting parts — can reduce material use, emissions, and more.

Use the infographic below for ideas on how to incorporate more sustainable practices into your design process.

Contact us today to get started.

The post 3 Design Strategies for More Sustainable Parts appeared first on SyBridge Technologies.

Additive manufacturing has ushered in a new era of manufacturing possibilities. 3D printing technology enables us to create previously ‘unmakeable’ parts, featuring complex dimensions and angles, with unprecedented speed and precision. However, the nature of the additive manufacturing process, in which material is added layer by layer, often means that parts require support to manage internal pressure–essentially, the force of gravity–during the print. Without that support, additive layers can’t be held up by the material around them and collapse, causing the print to fail. To address this challenge, we must sometimes design support structures into our 3D printed parts.

To ensure you maximize the potential of your 3D printed part for speed, quality, and cost, it’s important to understand support structures and how they should be integrated into your additive manufacturing project.

What are Support Structures in 3D Printing?

Support structures hold up elements of a 3D printed part which have no supporting material during manufacture. Not all 3D printing processes require support structures: while the Stratasys Fused Deposition Modeling (FDM), Carbon Digital Light Synthesis™ (DLS), and Stereolithography (SLA) processes often require supports, HP Multi Jet Fusion, which is a powder bed printing process, does not.

In the Stratasys Fused Deposition Modeling (FDM) additive manufacturing process, for example, layers of heated extruded material are built up from a print bed by adhesion to the material layers below them and may overhang those lower layers in order to create an angled surface. When that angle exceeds 45° the overhanging element generally requires support or the weight of the unsupported material will cause the element to collapse and the print to fail.

Where supports are required, they must be integrated into the part design and printed into the part when it is produced. Of course, this means accounting for the extra time and material that will be required during the 3D printing process and the subsequent post-process removal of the support structures.

Exceptions: Not all additive manufacturing methods require support structures. While 3D printing technologies such as fused deposition modeling (FDM) print parts by adding layers of material to a print bed, others, such as HP Multi Jet Fusion (MJF) print parts from a powder bed. Since the layers of powder are self-supporting, HP MJF part designs do not need to incorporate support structures.

What Types of Support Structures are Available?

Support structures for 3D printed parts vary in design and type but can be broadly organized into two categories: ‘trees’ and ‘fences’.

• Tree supports: Resembling branches or trunks, tree supports may enclose a part and fit neatly to angled surfaces for ease of removal. Tree supports can be designed, applied and tested quickly as part of a 3D printing project, enabling rapid iteration. Their branch-like structure means they can reach out over distances to support specific areas.
• Fence supports: Resembling walls, and with a variety of mounting points, fence supports are printed perpendicular to a part’s surface often with a lattice structure. Fence supports are more durable and easier to remove than tree supports, and are typically a better choice for cosmetic pieces or high volume production.

When Should I Use Additive Manufacturing Support Structures?

The ‘45° rule’ suggests that 3D printed overhangs of 45° and greater will require support, while those under 45° will not.

However The 45° rule should be considered a general rule of thumb and the need for support structures will vary depending on the complexity of part design and on the material being used. In some cases, bridging may offer an alternative to support structures: bridging is a technique in which heated additive material is stretched across a short distance (usually less than 5mm) without compromising the integrity of the part.

The ‘YHT’ principle: When conceived as 3D printed models, standing upright, the letters Y, H, and T are useful for illustrating the necessity for additive manufacturing support structures.

• The letter Y: Two arms extend from the letter Y at 45° – the angle of their overhang does not necessitate support structures. The further the overhang angle exceeds 45°, the more likely it is that support structures will be needed.
• The letter H: If the two vertical elements of the letter H are within 5 mm of each other, it may be possible to 3D print the horizontal element of the H with a bridge. If the vertical elements are further than 5mm apart, the horizontal element may require support structures.
• The letter T: The two arms of the letter T extend from the vertical element at 90° and will require support structures.

Beyond the angle of an overhang, other factors may affect the need for support structures. These include the quality of the 3D printer and the speed at which it prints: slower printers, for example, may increase the need for support structures.

Support Structures: Manufacturing Challenges

Support structures are a necessity in many additive builds but it’s important to remember that they can significantly affect the cost of a part in volume production — not to mention the amount of waste material that the project ultimately produces. Care should also be taken when removing support structures since they may damage or mark the finished part as they are detached.

With those factors in mind, 3D printed parts should ideally be designed to minimize or eliminate the need for support structures and, where possible, design for additive manufacturing (DFAM) principles should be applied in order to optimize parts for quality, cost, and production time. The following strategies may help to reduce the need for support structures:

Orientation: The orientation of parts on the print bed may affect the need for support structures. Overhangs, for example, may be eliminated by rotating a part onto its back or side. In the examples above, laying each of the 3D model letters Y, H, and T on their backs would completely eliminate any overhanging elements along with the need for support structures or bridges.

Part geometry: Where possible, remove overhangs from your design – or reduce their angle to less than 45°. Obviously, functional requirements may make the total elimination of overhangs impossible but you may be able to introduce alternative design elements such as chamfers, gussets, and radii to make the part’s geometry more self supporting.

Part separation: 3D printing technology enables the production of complex single parts, but if the amount of support those parts needs reduces their quality or cost-effectiveness it may be worth splitting the part into smaller components which can be assembled later. Spherical parts, for example, require substantial support but by splitting them in half, and creating a large flat surface, it’s possible to eliminate the need for supports completely.

Support density: The pressures exerted on support structures will dictate how strong they need to be and how much material is required to print them. To ensure a successful and cost-effective print, ensure your support structures are dense enough to support the size of the overhanging element. Bear in mind that the denser the support structure, the more difficult it may be to remove post-print.

Dissolvable supports: Some 3D printing technology may be able to print support structures in a separate dissolvable material, via a secondary print nozzle. These support structures can be submerged in water or chemicals, post-print, and dissolved to leave an intact part. Dissolvable supports reduce the potential for damage to the finished part during the support structure removal process. Most FDM additive materials have dissolvable supports, DLS and SLA materials do not. The HP MJF process does not require supports at all.

Getting Started

Support structures will continue to play an integral role in most additive manufacturing projects.

While the goal is always to reduce or eliminate the need for support structures, our engineers aim to optimize your part for functionality and cost. If you’d like to know more about how we can make your additive manufacturing project possible, contact the SyBridge team today.

The post Additive Support Structures: Why They Matter and How to Design for Them appeared first on SyBridge Technologies.

Whether you’re manufacturing parts for motorcycles or rebar-tying robots, you’ll need to start with a computer-aided design (CAD) file. These digital files contain 3D designs and other material, texture, and tolerance data to help product teams accurately plan, visualize, and manufacture the final product.

You have plenty of options when it’s time to export your CAD model, but different file formats are best-suited for different use-cases. Let’s take a look at STEP files, how they’re used, and their advantages and disadvantages so you can determine whether or not the STEP file format is the best fit for your project.

What is a STEP File?

Since other formats may require you to take intermediate conversion steps, STEP files (.step) were created to simplify saving and sharing three-dimensional models across CAD systems. STEP files go by many names including ISO 10303, STP, and P21, but STEP is actually an abbreviation for Standard for the Exchange of Product Data. The STEP file image format was developed in the mid-1980s by the International Organization for Standardization’s (ISO) TC 184, and the first edition of STEP came into use in 1994.

Every 3D STEP file contains three-dimensional model data stored in the widely recognized ASCII text code format. While some other file formats only represent basic geometries, STEP files will read and save a 3D model’s entire body with a high level of precision, allowing for more accurate file sharing and opening. Plus, since STEP files are plain text that appears as 3D models when opened in CAD programs, editing STEP files is simple. Likewise, it’s easy to view a STEP file’s creation date, original file name, application origin, and other metadata.

STEP files are commonly used in 3D modeling and architectural design due to their accuracy, cross-platform compatibility, and ability to create detailed models. Also, if you plan on CNC machining or injection molding a part, you’ll need to use STEP files because this file format enables machine tool path calculations.

The Pros and Cons of STEP Files

As one of the most popular neutral CAD formats, the STEP file format is compatible with countless programs. You can use STEP files with Autodesk Fusion 360, Dassault Systemes CATIA, FreeCAD, IMSI TurboCAD, SolidWorks, ArchiCAD, and more, making collaboration easy. Opening and editing files created in a newer software version in an older version — also known as downward compatibility — is also easy with STEP files, as they serve as intermediate links.

Another benefit of using a 3D STEP file format is that your file will store data using a non-uniform rational basis spline (NURBS). Using this mathematical representation of curves and basis splines (B-splines) results in greater flexibility, high dimensional accuracy, and smooth curves on the final product that would be impossible to achieve using triangle or polygon representations. That’s why many designers use STEP files for car bodies and other applications that require extreme precision and high levels of detail.

Since STEP files save the model as an entire body, you can customize and edit your models without losing any quality — even after exporting or re-uploading them. Plus, files in the STEP file format compress far more than source files, even though they’re around the same size. A compressed STEP file is typically 20% the size of a compressed source file, making STEP files better suited for sharing over the internet.

STEP files have a lot to offer, but they do have some drawbacks. For example, STEP files aren’t particularly storage efficient and will take up more space than other 3D model formats. They also don’t contain parametric intelligence; feature history; or camera, texture, material, and light data. Additionally, STEP files have an order set of procedural calls that reference other previously specified procedural calls, meaning it takes a lot of time and effort to create STEP files.

Unfortunately, you also can’t directly render STEP files with a graphics processing unit (GPU), and most renderers aren’t capable of loading STEP 3D files because of NURBS. Instead, you’ll need to convert your model into a series of small triangles for rendering using a software program.

STEP Files vs. STL Files — What’s the Difference?

STEP files and STL files are two of the most common file formats, but they each have their own characteristics. STL files only describe a model’s exterior geometry and simplify its features into a mesh made of triangles that’s free of gaps and overlaps, but STEP files save models as single entities and use NURBS, allowing for higher dimensional accuracy and smoother curves. As a result, STL files are lighter, simpler, and more storage-efficient than STEP files.

STEP files are better suited for when you need an extremely accurate model, have a curved part, or are injection molding or CNC machining parts. They are also easier than STL files to customize and edit after being exported, so if you’re planning to do lots of editing or collaborating, you may want to consider using STEP files. If you’re making a 3D-printed prototype, don’t need a high-fidelity product, don’t plan on making edits, or only have flat surfaces, you can use an STL file.

Luckily, you can convert a STEP file to STL by opening your file in the program you used to create it and exporting it as a different file type. At SyBridge, we convert STEP files to STL files whenever we need to 3D print a part.

Manufacturing With SyBridge

Many professionals in the manufacturing industry use the STEP file format because of its compatibility across programs and its ability to accurately represent curved surfaces. However, STEP files can be complex and aren’t necessarily the best option for every project. If you need help deciding which file format you should choose, work with a manufacturing partner like SyBridge.

Partnering with SyBridge gives you access to a team of qualified engineers who can answer questions and help you with every aspect of the manufacturing process, whether you need assistance with your design or advice on production. Contact us today to get started.

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