【125】From drawings to 3D modeling: Why do we "model" first before "manufacturing"?

【125】From drawings to 3D modeling: Why do we "model" first before "manufacturing"?

Customers often ask a question: We have the existing 2D drawings, why can't we just process according to the drawings? Why do we need an additional 3D modeling process? Is it because we want to charge more for the design fee?

This question was asked directly, and our answer was also direct: 2D drawings are the "photographs" of the product, while 3D models are the "living beings" of the product. Using 2D drawings to make molds is like creating a person by looking at a photograph – it can produce the shape, but it cannot create the soul. The soul that injection molding molds need to capture is the flow, contraction, crystallization, and orientation of the material under high temperature and high pressure – things that cannot be drawn on 2D drawings at all.

Let me tell you a real case. Last year, a bathroom equipment manufacturing company in Foshan took a 2D drawing of an imported product and wanted to make a mold to replace it. The drawing was very complete, with clear dimensions and clear tolerance requirements. According to the conventional approach, just following the drawing for processing would be enough. But we insisted on doing 3D modeling and mold flow analysis first. At that time, the client thought we were being overly cautious.

After the 3D model was completed and imported into the mold flow analysis software for simulation, a problem emerged: the difference in thickness between the thickest and thinnest parts of the product was four times. According to the original design with a single gate, the pressure of the melt when flowing to the thin-walled area had already decreased by 60%, making it impossible to fill fully. What's more troublesome is that the original design had an internal thread structure, and the ejection direction was perpendicular to the opening direction. A slider was required, but the movement trajectory of the slider interfered with another set of ejector pins. These two problems were completely invisible on the 2D drawings because 2D can only represent "static shapes" and cannot express "dynamic processes".

We sent the analysis results to the client. The product engineer of the client remained silent for a long time, and finally said, "I see why the imported parts use such special materials. It turns out that they are doing this to compensate for the defects in the mold design." Later, we redesigned the gate scheme, changed the single-point injection to a three-point sequential valve, and adjusted the slider structure. Only then was this mold successfully made. If we had processed it according to the drawings at that time, that mold would have been useless and wasted tens of thousands of dollars.

This is why we adhere to the principle of "building first, then doing". 3D modeling is not simply converting 2D lines into 3D shapes; instead, it involves "running through" every feature and every detail of the product in the virtual injection molding machine. Where the temperature is high, where the pressure is high, where the melt moves slowly, and where the cooling is uneven, all can be seen in advance. Identifying the problems allows for their resolution during the design stage; solving them in the computer means not having to wait until the trial molding site.

We have an unwritten rule: Before any mold is sent to the workshop from the drawing, it must undergo three rounds of mold flow analysis. The first round is a preliminary analysis to determine the location of the gate and the flow channel design; the second round is an optimization analysis to adjust the cooling system and balance the flow; the third round is a verification analysis to simulate the performance under different process parameters. After these three rounds, the mold has not yet started processing, but the product has already been "produced" hundreds of times in the computer. The trial molding on the machine is merely to verify the results in the computer in the real world.

A customer once asked: Is this worth it? Our response was: The cost of mold flow analysis is less than 5% of the cost of a medium-sized mold. However, it can prevent trial mold failures, save time costs, and ensure the delivery cycle. The value of these is dozens of times the cost of this analysis. Would you rather spend 5% of the money to achieve 95% certainty, or would you rather save this 5% and take a risk on an unknown outcome?

At Golden Eagle, we do not engage in gambling. We use 3D modeling and flow analysis to turn "possibilities" into "certainties".

Running a thousand times on the computer is not as good as running it just once in person? Wrong! Running a thousand times on the computer only requires one run in person.