DESIGN TIP: Choosing Industrial 3D Printing for Production Parts

Using 3D printing for fully functional end-use metal and plastic parts is becoming increasingly common in rapid manufacturing with industrial-grade processes like direct metal laser sintering (DMLS) and selective laser sintering (SLS).

Industrial-grade 3D printing is well suited to produce organic shapes, like this nylon turbine (left) and end-use production parts such as this titanium drill component (right).

With an expanding material selection and improving material properties, designers and engineers have another good option for small quantities of production parts.

Accordingly, our monthly design tip covers this emerging trend.

This month’s tip discusses:

  • Choosing the best 3D printing process for your application
  • Selecting the right thermoplastic and metal materials
  • Designing part geometry for 3D printing
  • Using SL, SLS, and DMLS for end-use production parts

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DESIGN TIP: Cutting Corners on Injection-Molded Parts

Sharp corners definitely have their place in part design, but they often spell trouble when injection molding plastic parts. Accordingly, designers should be aware of the pitfalls associated with “being square” when developing parts. Indeed, part accuracy, strength, and aesthetics suffer without the right amount of corner rounding and filleting.

This month’s design tip explores ways to strengthen injection-molded parts while reducing costs with proper placement of corner radii and fillet. You’ll learn about:

  • Material selection. Some plastics are more forgiving of sharp-cornered parts. Choosing the right one for your application is a necessary step towards accurate, functional parts.
  • Wall thickness. Beefing up adjacent walls may absorb some of the stress associated with sharp internal corners, but can create other design challenges.
  • Part geometry. Some parts are simply more “moldable” than others. Achieving proper form, fit and function depends on sound part design, a large piece of which is appropriate corner radii.

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On-Demand Webinar: Designing for Stereolithography

Last week we kicked off our webinar series on designing for 3D printing. The first session focused on stereolithography (SL) and it’s available on-demand here.

Key Takeaways

  • Properties of commonly used stereolithography materials
  • The unique benefits of stereolithography such as feature resolution and recommended applications
  • General design tips for overhangs, support structures, finishes and more

Top Questions

Can you describe the resolution of SL parts in terms of microns?
There are 25 microns per 0.001 in. Normal resolution builds in 100 micron layers, high-resolution builds in 50 micron layers and micro-resolution builds in 25 micron layers.

The minimum X/Y resolution would be 250 microns in normal resolution, 100 microns in high-resolution and 50 microns in micro-resolution.

What’s the cost difference between normal- and high-resolution SL parts?
There’s no set number since it depends on the part’s geometry. But for parts under 1 in., customers will see a relatively low cost difference between normal- and high-resolutions.

Height is a primary driver of cost so once you start approaching 2 to 3 in. build heights it can start to differentiate more dramatically. But, with our instant quoting process it’s easy to compare these costs simply by clicking back and forth and comparing resolutions.

What’s the rule of thumb for wall thickness in hollow structures?
We try to stay above 0.03 in. and a general rule is 0.01 in. wall thickness per inch of the part. For example, a part that’s 8 in., you’ll want to shoot for 0.08 in. wall thickness for a well-supported hollow part.

More 3D printing webinars on the way…
The next webinar on our calendar will be on accelerating medical device development with rapid prototyping, which you can sign up for here. And, in the coming months we’ll have more 3D printing webinars that will focus on designing for selective laser sintering as well as direct metal laser sintering.

DESIGN TIP: Improving Part Design with Uniform Wall Thickness

Designing parts with consistent wall thickness is a fundamental rule of plastic injection molding, and ignoring it can lead to sink, warp and inaccurate or non-functional parts. Yet the functional requirements of consumer, medical, aerospace and industrial products often leave designers little consideration for the material flow and fill properties of plastic, both of which are at least partially determined by wall thickness.

Pay close attention to rib-to-wall thickness ratios. To prevent sink, the thickness of the rib should be about half of the thickness of the wall.

This month’s tip discusses:

  • Guidelines to avoid cosmetic defects associated with thin and thick features
  • Material alternatives to improve wall thickness consistency
  • Important questions to ask about material properties
  • The benefits of design for manufacturability analysis

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6 Ways to Cut Machining Costs

The left image illustrates resulting corner radii from milling. Consider adding reliefs to sharp corners (right image) to improve fit.

Machining gets a bit more complex every year, and as a result, it can be challenging to keep pace with the do’s and don’ts of part design. But lowering the cost of machined parts while improving functionality can still be achieved by a few relatively simple adjustments to your part design or material selection.

Small tool diameters add machining time so consider removing text or logos from machined prototypes.

This month’s tip discusses:

  • Machining corner holes
  • Deburring edges
  • Avoiding unnecessary text
  • Keeping an eye on thin features
  • Reducing part complexity
  • Selecting material alternatives

READ FULL DESIGN TIP.