DFM - Design for manufacturing it's a bridge between product developer and mold manufacturer. It has been implemented in many manufacturing industries and proved to a sufficient way to improve efficiency. A comprehensive DFM report for mold making project would be the first step to success. As a mold maker, the more potential problems you foresee, the less risk you have in the manufacturing process
A DFM report's objective is to spot potential design flaws or advancements that could improve the process's efficacy, quality, and cost-effectiveness.
A DFM report is typically created by an injection molding expert or a manufacturing engineer. Because when designer or project responsible fails to design with manufacturing process in mind, they can run into many problems, including:
A design flaw or issue that makes it impossible to produce tools or parts.
Inefficient processes can later result in increased manufacturing or production costs.
Designers and engineers can address potential manufacturing difficulties proactively by completing a DFM report early in the product development phase, resulting in a more effective and economical injection molding process. This assists in preventing expensive design alterations or adjustments after the tooling process has started.
All parties involved in a properly completed DFM, including engineers, designers, contract manufacturers, mold builders, and material suppliers, must be involved. This "cross-functional" DFM's goal is to challenge the design and examine it from all angles, including the component, sub-system, system, and holistic levels, to make sure it is cost-effective and optimal.
The structure of DFM report
The DFM report need to include the following components:
Design analysis: An assessment of the product design's suitability for the injection molding process, looking for features that might be challenging or impossible to mold effectively.
Basic tool information: tool layout, cavities, tool dimension.
Gate location and type proposal.
Parting line definition: Suggestion of optimal locations for the main parting line and slider&lifer cores location and parting line.
Ejector pin location proposal.
Wall thickness analysis: Examination of wall thickness variations to ensure uniformity and avoid potential defects like warping or sink marks.
Draft angles: Checking the design for the presence of draft angles to facilitate easy ejection of the molded part from the mold.
Parting line and gate location: Suggestion of optimal locations for the parting line (the dividing line between mold halves) and gate (the entry point for molten material into the mold cavity).
Improvement proposal: Undercuts and features: Identification of any undercuts or complex features that may require additional design considerations or secondary operations. Rib design: Assessment of rib thickness and placement to reinforce the part without causing issues during molding.
Cooling channels proposal.
Mold flow analysis: Simulation of the injection molding process using computer-aided engineering tools to predict potential issues like air traps, weld lines, and flow imbalances.
Limitations
DFM is not very helpful, If Part designers do not use the data or take into account the suggestions from toolmakers DFM.
The goal is to design a product that is easily and economically too manufactured.
Design decisions contribute to 75% of a product's manufacturing costs (materials, processing, and assembly expenses).
Only 25% of costs is correlating with production decisions such as process planning or machine tool selection.
It is crucial that there is enough time to complete DFM, specially during the design process.
If a DFM report is available and there is not enough time for further improvements to be made, failures and potential issues in the future will result from this, without a doubt. This will add time to the manufacturing process, cause delays, and result in significantly higher expenses.
Virtual measurements
Remarks and other improvements are covered in the final chapter of DFM.
You should definitely do virtual measurements of a 3D deformed part.
What does that mean?
It is essentially the same process as measuring produced components (parts), where you compare scanned part and CAD data.
When you perform virtual measurements you use a 3d warped - deformed model that is the result of a Moldflow analysis (instead of scanned data)..
We use GOM inspect software to do visual inspection comparison.
More about Virtual measurement you can read in the next post - Virtual measurements or click here.
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