Page 95 - Injection Molding Advanced Troubleshooting Guide
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8.7 Machine Documentation 79
Distance between tie bars
Screw type
Screw L/D
Screw compression ratio
Screw diameter
Intensification ratio
Tonnage
Shot size
Maximum fill rate
Maximum injection pressure
For ease of access create plaques that can be mounted on the machine to provide
key data. Figure 8.18 is an example of machine data that can be posted on a mold-
ing machine. A key to people using machine data is making it readily accessible.
Figure 8.18 Example of a machine data plaque
Repeatable molded parts need to be produced with a repeatable process and a re-
peatable process requires a repeatable machine. Avoid processing around machine
problems or otherwise the process window will be reduced, which will result in
scrap and PPM problems.
If a mold is to be validated in multiple machines the lowest common denominator
will be what the process should be established at. For example, if a mold is vali-
dated in a primary and secondary machine the first-stage speed cannot be set
faster than both machines can obtain. Clear documentation of machine details
provides for quick analysis of whether a job will run in a given machine.
References
[1] Bozzelli J., Groleau R., and Ward N. “The Machine Audit: A Systematic Evaluation of Injection
Molding Machines: How to Tell a Good Machine—Old or New” Antec 1993.
[2] Doyle K., “Know Your Machine”, Plastics Technology, May 2014.
[3] Bozzelli J., “Know the Basics of Machine Evaluation, Part 1”, Plastics Technology, June 2010.
