Course: Correct design – Bosses in plastic parts

44.07 $ incl. tax


Bosses exist as screw or plug connection in many plastic parts.
Commonly these areas lead to defects such as sink marks, air traps, weld lines or incomplete filling.

This course explains why the defects appear.
With the help of injection molding simulation, the animation and pictures show how the wall thickness in a single boss and at its bottom influences the quality of the part.

The filling and packing phase will be discussed equally to find the best possible wall thicknesses for bosses.

SKU: EL7855 Category: Tag:

You will learn

  • How to optimize the wall thickness of the bosses for filling and packing phase
  • How to estimate the best wall thickness underneath the bosses
  • To determine the radius around the bosses

This enables you to

  • Design bosses the best way
  • Save cycle time and money
  • Improve the quality of parts


About Correct Design - Bosses in plastic parts

Many part designers have studied mechanical engineering and used mainly metals in their design work. The necessary differentiation by designing a metal or plastic part is therefore a lot of times unknown.
However, it is truly mandatory, as the correct design of the plastic part saves material, cycle time and therefore money. A plastic part design makes the cooling of the mold easier, because less hot spots will appear. Furthermore, the first trial will be more successful, because less defects will be visible at the part, which need to be corrected.

This course describes the design of bosses in plastic parts.
Bosses can be found in almost every part. They are needed to realize screw or plug connections. Therefore, it is important to understand how to design bosses in the best way.
With the help of injection molding simulation, the filling behaviour of the bosses is discussed first. Different wall thicknesses will be checked and evaluated.
In the packing phase, sink marks and voids are discussed, as well as the volumetric shrinkage and the molten core.
At the end of the course, a compromise between the found results is made to get the best wall thickness for the bosses.

The approaches with animation and pictures are easy to understand and well comprehensible explained.


This course is for

  • Part designer
  • CAE-Team
  • Quality manager
  • Department leader
  • Simulation-Team
  • Project manager
  • Head of design
  • Key account manager
  • Management


Course details

For basic skill level

Around 60 min in duration

Video On-Demand lessons (1)

Spoken script by the author

Expertise knowledge described step-by-step in text

Additional explanations on important technical terms

Full access on computer or mobile for one year

(1) Video streaming is part of the e-learning and shall be accessible in your browser.

Course Specialist

Dipl. Ing. (FH) Berthold Neuhäuser


CEO at IBN-Plast

I earned more than 15 years experience with injection molding simulation, warpage as well as structural analysis during my work in my engineering office (IBN-Plast).


11 years of experience build up in quality assurance (supplier management), Audits (e.g. VDA 6.3) at Bosch Automotive and Bosch Home Appliances.
Since 6 years, I have been working with different 3D printers for prototyping and near-series production at IBN-Plast.


I have 5 years of experience in manufacturing and control of technical compounds, as well as their use. I was responsible for testing of plastic granulate and its technical use, as well as processing and developing solutions of customer service complains. (CP Polymertechnik).
In addition to that, I have 6 years of experience working as service manager for different IT companies.