DFM: evaluating the manufacturability of a product design

1 May 2018

The process of developing a new plastic product starts with the right design. Before we ask our toolmaker to produce a new mould, Rompa always executes a DFM process during which we evaluate the manufacturability of the customer’s product design. 

What is DFM?
DFM is short for “design for manufacturing.” During the DFM process, we evaluate the manufacturability of the product design. Rompa always does this in close collaboration with both the customer and the toolmaker responsible for producing the mould. The goal of DFM is to create a design together that meets the demands and wishes of the customer and can actually be realised with an efficient process. Based on this design, we draw up the specifications for the mould.


Quality assurance
As an injection moulding company, it is our responsibility to make sure that the plastic product comes out of the mould in the desired manner and that the customer receives the quantities it wants when it wants them. Using the right mould design is therefore essential. The mould design depends on both the product design and the material being used. The mould’s lifecycle partially depends on the product design, which is why Rompa handles the DFM process with such care. On average, a DFM process takes two weeks, although it can take as long as three or even four weeks for more complex products.

                           Draft of hydraulic slides

                  Filling of mould in seconds

How does DFM work?
A DFM process consists of two phases. During the initial phase, we evaluate the concept in general terms by focusing on key issues, such as which part of the product will fit into which part of the mould (cavity and core). This determines where the product will show markings and weld lines. We also check whether there is sufficient ejection space, where the sliders should be and how and where the plastic should be injected. During the second phase, we take a closer look at the fine details of the product design. For example, we check the texture in combination with the ejection, whether the plastic can be cooled properly and if the mould’s steel is thin (and therefore weaker) anywhere.


DFM checklist
Below, you can see an overview of the twenty aspects on which Rompa, the customer and the toolmaker evaluate a product design during a DFM process. We use this checklist consistently for every product.

1. Part overview 11. Part marking/engravings
2. Cavity and core impression 12. Cooling layout
3. Slider impression 13. Filling
4. Mould layout 14. Analysis of wall thickness
5. Gate location and type 15. Weld lines
6. Parting lines 16. Air traps
7. Draft analyses 17. Mould flow
8. Part ejection 18. Product-dedicated mould risks
9. Weak steel 19. Warpage
10. Undercuts 20. Identify possible quality issues

After DFM
Once the design has been approved by all parties, we release it and record the final specifications for the mould. The toolmaker can then start developing the mould. Before the serial production process starts, we test any new mould extensively by conducting mould trials to safeguard the quality of the process.


What makes Rompa’s DFM process so special?

  • •  Highly detailed outline of the DFM process;
  • •  Proactive: we give our feedback on the design before being awarded a project. Resolving any issues with the design at an early stage can help to reduce the project’s lead time.
  • •  Because we offer feedback early on, a customer gets to know our organisation right away and our collaboration is off to a great start.