Car Dashboard Lenses

RYD Tooling has helped an American client with a design improvement to achieve a better surface finish on parts.


Our customer came to us to make a mold for the car dashboard lens and asked for optical polishing. Based on the RYD team’s analysis of the 3D drawing design of the lens and the customer’s requirements, we suggested our customer to improve the product design. In order to obtain the optical polishing level, the customer adopted our Suggestions and made the modification. At last, we made the perfect T1 samples and our customer was satisfied with them.


The polished surface is required to be flat without any bumps or dents, no structure, so that the machine can polish the entire surface. The solution of parting line for this product does not meet the polishing requirement. See the picture.
Red lines are the original 3D part design’s parting line, which means that the parting surface of the cavity is not a plane, only manual optical polishing process can make it, the optical polishing machine can’t be used to polish. In this case, the perfect optical polishing can’t be done for sure. How were we going to do next? Please see the “What we did”.

What we did : Solution 1

If there is no impact on the assembly and functional quality, we suggest that only the red shaded surface be optically polished. By this way we can make the red shaded parts as a mold insert, this insert has the flat surface so we can use the optical polishing machine to polish it.

What we did: Solution 2

We suggest moving the parting line to the top so that the cavity surface is also flat, which can be polished by the optical polishing machine.
Our customer prefer to the solution 2. That would be the one.

Other Technics

S-shaped runner indicated our rich experience in manufacturing transparent lenses mold. It makes the molding debug smoother, avoids the air marks, flow marks and other issues in injection molding.

Mold Flow Analysis

The mold flow analysis helps us and the customer understand how the products molded and avoids some unpredictable situation, somehow it proves the whole solution is feasible.


The mold runs well on the injection molding machine, the samples and products are perfect without any distortion.


Part Name:                   Dashboard Lens

Part Material:               PMMA

Mold Cavities:              2 Cavities

Steel of Cavity/Core:   ASSAB S136 Hardened

Mold Life:                      1,000,000

Mold Dimension:         500*550*540 mm

Standard Parts:            DME inch

Polishing Grade:          Optical Polishing

Ejection:                        2-stage Ejection

Our Customer Say

Hello Bruce:

“Again, thank you for all of your support. You and the RYD team couldn’t be more accommodating and professional during this tooling build.”

Mr. David

And after the first samples testing, here is what David said:

– I have just finish testing of the six lenses together with two assemblies:

– All six lenses assembled mounted properly into final assembly,

– All snaps engaged properly with the housing,

– Button did fit properly into all six lenses,

– Trim ring snaps did engage properly with the lens,

– The outside and inside surface of the visible area was good.

– I will do the measurements to verify dimensions.

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