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3D-Printed Injection Molds

Helin, David LU and Palmér, Kristoffer LU (2020) MMKM05 20192
Product Development
Abstract
This master thesis describes the development process of a prototyping process. It
was carried out in collaboration with Axis Communications.
When creating plastic prototypes, development engineers usually have two
options, 3D-printing or injection molding using a soft tool. 3D-printing allows for
fast and relatively cheap creation of prototypes which contributes to a fast product
development process, but the physical properties are not the same as in the final
product. Injection molding using a soft tool creates prototypes of high quality with
physical properties equal to the final product, but it is time consuming and costly.
The purpose of the project was to investigate the possibility of 3D-printing
injection molds for... (More)
This master thesis describes the development process of a prototyping process. It
was carried out in collaboration with Axis Communications.
When creating plastic prototypes, development engineers usually have two
options, 3D-printing or injection molding using a soft tool. 3D-printing allows for
fast and relatively cheap creation of prototypes which contributes to a fast product
development process, but the physical properties are not the same as in the final
product. Injection molding using a soft tool creates prototypes of high quality with
physical properties equal to the final product, but it is time consuming and costly.
The purpose of the project was to investigate the possibility of 3D-printing
injection molds for prototyping and to create a process where the method is used.
This would combine the two prototyping options into a process that would be
situated between them, allowing faster prototyping than injection molding using a
soft tool while also creating better quality prototypes than 3D-printing.
Through external and internal research, including interviews and physical tests
with an injection molder, a greater understanding of the subject was achieved and
experience regarding the problems related to the process were identified. The
information gathered was then turned into target specifications.
To reach the target specifications multiple design concepts and mold materials
were tested before a final selection was conducted. One mold material and eight
design concepts were selected for the process. The design concepts solve different
problems which can not be solved directly by the selection of mold material.
The results are summarized as an instruction of how to use the process and a
recommendation of how to further develop it. (Less)
Popular Abstract
In product development projects it is important to test the physical parts to see that they fulfill their
intended use before production. The use of prototypes such as 3D-printed parts are therefore becoming
more common in many industries. But even though 3D-printed parts looks like the end product they
seldom act the same, which reduces the usefulness of these prototypes. The purpose of the thesis was
therefore to create a prototyping process which creates higher quality prototypes with the help of 3Dprinted injection molds.
When creating plastic prototypes in product development projects it is important to make sure that the
prototypes are as similar to the end product as possible, this to ensure reliable test results that can be
... (More)
In product development projects it is important to test the physical parts to see that they fulfill their
intended use before production. The use of prototypes such as 3D-printed parts are therefore becoming
more common in many industries. But even though 3D-printed parts looks like the end product they
seldom act the same, which reduces the usefulness of these prototypes. The purpose of the thesis was
therefore to create a prototyping process which creates higher quality prototypes with the help of 3Dprinted injection molds.
When creating plastic prototypes in product development projects it is important to make sure that the
prototypes are as similar to the end product as possible, this to ensure reliable test results that can be
evaluated. These prototypes do however often only resemble the end product in the look and seldom in
material properties and the manufacturing method. This makes the usefulness of many prototypes limited
as some physical tests cannot be conducted until the real end product is produced, rendering a risk that
they will not act as predicted.
When manufacturing plastic components the most common method to use is injection molding which
uses a metal mold to form the plastic under high temperature and pressure. In order replicated this method
the thesis used 3d-printed molds which then were injected with melted plastic in a similar way to mass
produced products.
Since injection molding is a fairly complex production method and injection molding in 3d-printed plastic
molds are even harder some design concepts of the new molds were created. These concepts revolved
around the cooling, degree of filling, ejection and life span of the molds. Since parts that need to be
created can differ in many ways the different concepts were applied when problems were encountered.
With the help of the design concepts, nine 3D-printing materials that were deemed interesting for the
process was tested during a material test run. Only one of these was capable of high temperature injection
molding. This material was Digital-ABS, which is a thermoset plastic developed by Stratasys for its 3Dprinting machines. Injection molds made with this material were able to create high temperature plastic
prototypes in the plastic PC-ABS without signs of damage. The prototypes were highly detailed, fully
filled and had an easy release from the mold which indicates that the process has potential in being used
as a replacement for 3D-printing in some specific use cases.
Since the process is fairly complex it is best applied in tests were the function of the part cannot be
verified by other methods. Tests such as heat and impact, or when making prototypes that are exposed to
mechanical stress like snap-fits.

Master thesis written by David Helin and Kristoffer Palmér at the Division of Product Development,
Faculty of Engineering LTH, Lund University. (Less)
Please use this url to cite or link to this publication:
author
Helin, David LU and Palmér, Kristoffer LU
supervisor
organization
course
MMKM05 20192
year
type
H2 - Master's Degree (Two Years)
subject
keywords
Product development, Prototyping, Additive manufacturing, Injection molding, 3D-Printing
language
English
id
9003755
date added to LUP
2020-02-03 10:30:11
date last changed
2020-02-03 10:30:11
@misc{9003755,
  abstract     = {This master thesis describes the development process of a prototyping process. It
was carried out in collaboration with Axis Communications.
When creating plastic prototypes, development engineers usually have two
options, 3D-printing or injection molding using a soft tool. 3D-printing allows for
fast and relatively cheap creation of prototypes which contributes to a fast product
development process, but the physical properties are not the same as in the final
product. Injection molding using a soft tool creates prototypes of high quality with
physical properties equal to the final product, but it is time consuming and costly.
The purpose of the project was to investigate the possibility of 3D-printing
injection molds for prototyping and to create a process where the method is used.
This would combine the two prototyping options into a process that would be
situated between them, allowing faster prototyping than injection molding using a
soft tool while also creating better quality prototypes than 3D-printing.
Through external and internal research, including interviews and physical tests
with an injection molder, a greater understanding of the subject was achieved and
experience regarding the problems related to the process were identified. The
information gathered was then turned into target specifications.
To reach the target specifications multiple design concepts and mold materials
were tested before a final selection was conducted. One mold material and eight
design concepts were selected for the process. The design concepts solve different
problems which can not be solved directly by the selection of mold material.
The results are summarized as an instruction of how to use the process and a
recommendation of how to further develop it.},
  author       = {Helin, David and Palmér, Kristoffer},
  keyword      = {Product development,Prototyping,Additive manufacturing,Injection molding,3D-Printing},
  language     = {eng},
  note         = {Student Paper},
  title        = {3D-Printed Injection Molds},
  year         = {2020},
}