Design guidelines and design optimizations for plastic 3D printing

For the additive manufacturing of plastic parts, there is less restriction in construction than in most conventional methods, such as. As the injection molding. In particular, this applies to powder bed-based 3D printing processes (eg multi-jet fusion ) in which (almost) any design is possible.

Plastic components designed and optimized for injection molding or machining can usually also be produced using the Multi Jet Fusion process. However, it is recommended, especially for larger quantities, to optimize 3D printing (“design for additive manufacturing – DFAM”).

On this page we have compiled some recommendations for the design of additively manufactured components:

  • Requirements for the 3D file
  • Printability & Design Guidelines
  • Design optimization for 3D printing

1. Requirements for the 3D file

For a 3D print is required for the object to be printed as a digital model. The models are created using CAD, 3D design programs or a 3D scan.

With common design programs, such as Inventor, Fusion360 or Solidworks, the model can be exported without problems in standard formats such as STP or STL. A check (with the exception of the file format) is usually not required.

For older software versionsless common design programs, 3D design or architecture programs, and 3D scanning, we recommend that you adhere to the requirements listed here.

In addition to the requirements, you will also find links to instructions with suggested solutions:

File formats

3D printing requires data in the form of 3D models. The following formats have prevailed:

  • STP: CAD format, which can be exported from all common CAD programs. Less used is the outdated format IGES, which contains similar information.
  • STL, OBJ: Mesh files, which can also be exported from almost all common programs. For mesh files, it should be noted that the resolution is not too low (~ 0.01 – 0.05 mm), since otherwise it may lead to quality limitations. If you are unsure about the resolution, you are also welcome to send us the STP records.

Please note: Based on pictures, drawings and photos unfortunately cannot be printed 3D or an offer can be created.

2. Printability & Design Guidelines

The basic design requirements for additive manufacturing with the Multi Jet Fusion process are manageable. In particular, wall thicknesses, channels and the correct dimensioning must be taken into account.

If these requirements are fulfilled, the object can be manufactured. In order to further optimize the result.  To learn more about the 3D modeling and CAD programs log on to FORT Education Training Center in Coimbatore.

Channels and blind holes

A channel is a recess in an otherwise massive structure that has an entrance and an exit, a tube, as it were. Additive manufacturing with powder bed-based 3D printing enables you to directly print channels or blind holes (only one opening).

Problem situation:

If channels or blind holes are printed directly, the problem often arises that the unneeded material powder must also be removed from the channel. This can be difficult with winding or winding channels, as the air jet does not reach the entire channel to discharge the material. Or the material collects at the bends and clogs the channel.

Solutions:

For straight blind holes or channels, a simple re-drilling is possible, which removes the excess material usually reliable. However, it is important here, a minimum diameter of 2 mm .

For curved channels, the diameter should be as large as possible. Another possibility is to constructively integrate a type of wire or chain into the channel . This element is pulled out during cleaning, so that a large part of the “filling material” within the channel is loosened and removed. The remaining material can then be more easily removed from the channel.

The wire should have a minimum diameter of 1 mm and a clearance of at least 0.5 mm to the channel wall , with larger channels correspondingly more.

3. Design optimization for 3D printing

If all the requirements in sections 1 and 2 are fulfilled, the object can be printed. However, this does not always lead to the desired result.

This section provides guidance on how to optimize the design for 3D printing in terms of function or cost.

Especially with higher quantities or the use of the component as a functional part, a corresponding review or adaptation of the model is recommended.

Stability of the elements

Stability of the workpieces:

Since the advent of 3D printing, there is a belief that everything is 3D printable. For geometric shapes this is true to some extent. However, the 3D printed structures also have to wear and be stable. Say – even in 3D printing, the laws of physics apply.

Problem situation:

Using the 3D model, it is not always clear whether the object is stable after 3D printing. If filigree structures are to carry a larger block of material on their own, it is easy to break off the structure. If the wall thicknesses are too low, the weight of the structure sometimes suffices to cause a break.

Design Notes:

Check that load-bearing structures can withstand the load. In most cases, CAD programs have the ability to check the stability of individual elements and, if necessary, to reinforce critical elements or to insert additional structures. Also, check for the Solidedge training center in Coimbatore.

 

 

 

 

 

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