Unlike most industrial materials rubber surfaces might be elastic, meaning if you put a little pressure on it, it will curve even if it’s not visible to the naked eye.
This can cause some difficulties when wanting to do in-process dimension inspection or even off-line measurements. The traditional touch probes distort the results and when very accurate measurements are needed they become inapplicable. Standard rubber surface measurement requires an approximate of 50-100micron accuracy.
In the non-contact measuring field there are quite a few methods. While most of them are good for flat surfaces and small angles, when it comes to complex surfaces with steep angles or narrow gaps they fail to retrieve the full metrological data (more on that can be found in our earlier blog posts).
The only way to do optical measurements of these applications is a collinear measurement. A good example is the tire industry. There is a need to measure the sipes and grooves which run across the tire. The depth, width and angles of these narrow canals are very important for the tire’s grip on the road and prevent skidding especially when it’s wet. Another industry with the same needs is shoe sole manufacturing. It turns out there’s a lot of science in the groove designs on the bottom of your shoe which need to be measured and approved.
But perhaps one of the most challenging applications is vacuum suction cups which are used in many industries and places, from regular home printers to industrial glass grippers. The angles and height differences are very important and if they don’t come out from the injection mold properly the function failure is just a matter of time.
Optimet develops and manufactures non-contact, collinear distance measurement sensors, and has much experience in measuring soft and hard rubber of any type, even if it’s black with very low light reflection. For a black and absorbent surface Optimet has a special sensor with higher laser power – the CP-20.
Contact us for more information on your particular application challenge.