How to machine a gap between the hole and the shaft that is below 10 micrometers?
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Air bearings need to be developed; in order to improve the precision of spindles in the future, it is necessary to design an air film gap of less than 10 microns. In other words, the radial gap between the hole and the shaft must be controlled at around 10 microns. What manufacturing methods can be used to achieve such high precision? Thank you
The grinding process is employed, whereby both the hole and the shaft are ground after turning, using internal and external grinders respectively, to determine their final dimensions.
Matching the grind is possible. First, machine the hole, then select the shaft for matching. If only one set is to be made, drill the holes first, and determine the grinding allowance for the shaft based on the actual dimensions of the holes and the required clearance.
Generally, we use the hole as a reference point; the tolerance for the hole can be H7 or H8. Based on the actual size of the hole after machining, the tolerance for the dimensions of the shaft is determined, so that the fit clearance remains within the desired range.
With proper grinding, this precision should be achievable
In such cases, customized development is necessary; relying solely on improving manufacturing precision for mass production is not cost-effective
Could you explain the specific process of \"grinding\"?
For single pieces or small batches, fitting and grinding will suffice; it’s a different matter for large batches
Matching the dimensions should be possible; the shaft can be turned first and then ground, while for holes, it’s better to use grinding by erosion. (But according to the original poster’s requirement, the air film gap is supposed to be 10 microns – I’m not sure what that entails. The hole walls resulting from erosion have a fine network-like structure; will this have an impact on the product?) ）
It’s not easy to achieve precision turning either; let’s use a grinding machine instead
Our factory outsources all the processing to external parties