Hi Ashish
From your 3D model it would have been best to coninue with the profile cutting of the purple plane with the 4th axis locked.
It would have been helpful if you had included some dimensions as the approach will be different depending upon the size of the part and the accuracy required. Also the surface finish of the red face and the orange in your sketch will also impact on the end resulting accuracy.
As the job has been started using the blue part as the reference you may like to consider continuing to hold the workby the blue surface. Clamp in a vee block to the XY table. The vee block can then be shimmed as necessary to bring the red face to a satisfactory degree of tramming to the Z axis.
Again size of the red surface and the final alignment of the red and purple machining planes is necessary as this will dictate the degree of difficulty you face. If the red fac
e is 200mm square problem is very different from the one in which the rd face is only a few mm square. Obvious but all too easy to miss when in a CAD drawing stage.
I still think the production process needed to consider the end result. I assume this is a retro modification in which case you the finished product / cost to start again and machine the critical faces at one setting or to have a sacrificial part such as your blue zone that is easy to reference - think square bar stock - prepare two faces as reference surfaces / edges from which all dimensions are made. The sacraficial paert being removed as the final machining operation.
You need a sensitive way of tramming the red face to the Z axis if you are going to achieve your goal of a few microns. Consider making a jig that will fit in the Z axis collet. The end surface being machined square i.e. is orthagonal to the Z axis. The red face of the work should then be clamped hard to the jig and care taken to shim a vee block to support the lck and shims. However this will be tedious and have to be repeated for each and every part.
If you need better accuracy then consider mounting a glass optical flat orthagonally to the Z axis. The flat must over hang the jig so that you can see \through the glass. Lower the glass flat onto the red plane of the work very slowly with some thin oil or even water on the red surface. As the glass flat approaches the red face the liquid will suddenly flood the face of the glass. Withdrawing the Z axis will streach the liquid film and you will see if the breakaway is even or if one edge consistently breaks first in which cas that edge is low and is adjusted and the process repeated. With a ground face on the red part you should achieve a good indication with water and a drop os detergent or photographic wetting agent in the water. This is very very tedious and you may like to consider starting to make the parts again.
Hope this helps crystalise your thoughts.
Regards
Pat  |