Lesson 5 - The production process
In the previous times we defined basic concepts, designed the product, planned it
We created a model and tested it from every possible angle:
We changed, improved, corrected and arrived at an optimal final product.
Now it's time to go to production.
Mold design
Mold design begins with a design for manufacturing (DFM) review. This document sets out the key requirements and design decisions that will guide mold design and manufacturing:
Material type and shrinkage
Parting line location
Runner system and gate location
Side-action slides for undercuts
Part ejection method and ejector pin locations
Required surface finish
Example of DFM at this link
Mold design begins after the customer approves the design for manufacturing (DFM) review. The quality of the preparation work has a direct effect on this stage: a product designed for injection molding generally requires fewer last-minute changes.
Testing with a prototype mold can help identify necessary changes before the production mold is designed. Any change to the product requires the customer's involvement and approval.
The completed design is a 3D model containing the mold components and providing the basis for mold manufacturing.
Tip #5:
Only your high involvement as a customer will ensure the desired result.
Therefore, I recommend requiring the manufacturer to receive a DFM document,
and check it very carefully before approving it.
Mold manufacturing
It is a complex process that includes processing metals using many different methods, including:
• Milling
• Sharpening
• Electro erosion deposition
• Electro erosion - wire cutting
• Engraving
• Drilling
• Sawing
• Polishing
• Photochemical burn
• sand bkasting
We manufacture mold components from steel grades selected for the required hardness and performance. The components are assembled and fitted until the mold operates correctly.
A typical mold may require an accuracy of 0.02 mm. Some medical and high-tech applications require even tighter tolerances. Mold manufacturing involves many hours of precision work. The images below illustrate examples of molds.
The two mold halves, side by side
Open mold
Molding trials
The final stage of mold manufacturing is a molding trial. A small batch of parts is produced to check that the mold operates correctly.
The parts are checked for dimensions and function. For an electronic device, for example, the circuits and other components are assembled into the molded parts so that the complete device can be tested.
Making adjustments and changes
If no prototype has been made, molding trials are likely to reveal changes needed in the product. Injection molding involves uncertainty because plastic shrinks and can warp, so the first trial parts are often followed by adjustments and further trials.
Several rounds may be needed to reach the required result. Mold manufacturing is completed once the mold and product are approved, after which regular part production can begin.
For medical products requiring testing and validation, an initial small batch is produced for the relevant assessment before regular production.
We are nearing the end of the introductory series.
Next time we will talk about the production of the first series and ongoing series.
In the meantime, I will be happy to answer questions by email: boaz@plastomold.com
thanks and have a good day,
Boaz