Hello and welcome to a new Rule of Thumb blog post. Today we discuss the 4M approach for effective troubleshooting in polymer injection moulding.
Background
of the 4M approach
In general,
troubleshooting in injection moulding means to solve problems which are related
to the part, mould, machine, material, or process. The 4M approach was coined
by Mr. Kerkstra and Mr. Brammer and is a systematic way to solve injection
moulding issues. As a troubleshooter you can influence 4 main areas:
1. Moulding process
2. Mould
3. Machine
4. Material
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| 4M approach for systematic troubleshooting in injection moulding |
During troubleshooting,
potential root causes can be hidden behind each of the 4M’s. Using the 4M
approach allows you to systematically work through one category at the time and
create a list of potential root causes.
Always
ask: ''which of the 4M’s could be the reason for the defect and why?” Getting
to the root cause is key. Also, avoid processing around issues when in reality
a change in the tool is needed.
Another trap
in troubleshooting is trying to solve the wrong problem. For example, one is
reducing the injection speed to avoid burns, however the real reason for the
burn are blocked vents in the mould. Therefore, one may always ask what has
changed in the mould, material, moulding process or machine setting.
Additionally,
working to solve a potential root cause at a time and to do so collecting data
is key. One can change a thing and then observe the impact. Changing several
processing settings at the same time will make it impossible to solve any
problem. And if there is no impact when you have done the change, then
switching back to the original documented setting is fine.
What are some additional troubleshooting techniques?
There are several additional troubleshooting
techniques, such as
-5 Why
-Scrap
recording sheets
-Brainstorming
-Fishbone
diagram
-Is/Is Not
analysis
-Design of experiments (DOE)
Main takeaways
Asking
questions and exploring answers is a main task in troubleshooting. Also it is
important to check if the moulding problem is a new one or is already longer
there. In case it is a new problem, one needs to dig in and find out what may
have changed. Only change one thing at the time. The moulding process takes
time to stabilize and to see the effect. Another point to pay attention to is
that the medicine should not make you sick, meaning that the problem solved
should not create new problems.
Successful
troubleshooting combines knowledge, a systematic approach and experience
Additionally, I made a short training video on
injection moulding troubleshooting, which you can find here.
Thank you for reading and #findoutaboutplastics
Herwig
Interested to talk with me about your plastic selection and part design needs - here you can contact me
Literature:
[1] Kerkstra / Brammer: Injection Molding Advanced
Troubleshooting Guide, The 4M Approach
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