Machining compensation experiment – progress report J.Huopana

Main idea 1.CAD/CAM- softwares are used to design the geometry and the manufacturing 2.Machining of the piece 3.Measuring the machined surface 4.Results of the measurements are analyzed and the reasons for the errors determined. Based on these findings a new geometry will be created in the CAD/CAM environment to compensate the found errors. 5.A new piece will be machined 6.Result: better accuracy compared to the first

Hermle C30U +/- 3-5 µm X-axis range 905 mm Y-axis range 1605 mm Z-axis range 605 mm Resolution mm Accuracy mm Resolution mm Accuracy 1.7 µm Mitutoyo Series 355 Euro Apex Strato 9166 Toolbox Experience & ideas

Hermle C30U X-axis range 905 mm Y-axis range 1605 mm Z-axis range 605 mm Resolution mm Accuracy mm Resolution mm Accuracy 1.7 µm Mitutoyo Series 355 Euro Apex Strato 9166 Toolbox Experience & ideas Hermle C30U +/- 3-5 µm

Shape has been extracted from VG1 (CLIAAS110001) Green surfaces are designed for metrology Shape tolerance goal better than +/- 5 µm Modeled in CATIA and in MasterCAM Test piece CAD/CAM design

Machining -5-axis machine -One axis is used to tilt the test piece to have more material to remove -After the tilting (5 deg), machining is 3-axis the machine is stabilized (respectively) Air condition, 6 hours of operation before starting the machining

Contact Measuring Machine Five profile measurements 1.45 deg profile (shape1) 2.Profile from the right (shape 2) 3.Profile from the left (shape 3) 4.45 deg profile to the opposite direction (shape 4) 5.Profile from the bottom of the cell (shape 5) Shape 1 Shape 2 Shape 3 Shape 4 Shape 5

Tests 2 main strategies to machine the piece (surface) Both were machined and measured to determine the ”right” method

Test piece 1

Iris 2

Cross-section

Test piece 1 surface quality, considering Ra 0,2, is not achievable with current cutting speed of rpm (not a goal in this study) problematic connection of surfaces visible, might be possible to fix with changes in CAM burrs visible, also possible to improve the situation by changing CAM-design

Test piece 2

Test 2, Iris 2

Cross-section

-changes were made for the tooling directions and movement to have smoother surface in the iris area and to remove burrs -changes were made according the first test -a error of 6 µm visible in every shape => Tool length (0.006 mm) Test piece 2

Test 2 + 6µm (y) (simulation)

Test 2 + 6µm (y), Iris 2 (simulation)

Test 2 Cross-section + 6µm (y)

Results of the first two tests

What happens when you compensate to the wrong direction?

This Test 3

What happens when you compensate to the wrong direction? This Test 3 MURPHY'S LAW §15. ”In an instrument or device characterized by a number of plus-or-minus errors, the total error will be the sum of all the errors adding in the same direction.”

Test µm (y) (simulation)

Future work Compensate the tool length Compensate the bending of the piece Measuring and verifying the effectiveness of the method

That’s all folks.