1. CLIC Meeting 21/08/2001 G. Arnau Izquierdo EST/SM 1 W single crystal advancement. 1) Manufacturing. 2) Images after EDM. 3) Images after grinding. 3) Images after electropolishing. 4) Conclusions.

2. CLIC Meeting 21/08/2001G. Arnau Izquierdo EST/SM2 Manufacturing of discs. W single crystal EDM: Electrical Discharge Machining = Electro-erosion EP: Electropolishing EDM cutting Grinding EP: -12.6µm EDM conditions are similar than for the CERN Workshop irises. They can be optimised for better finishing. Grinding was feasible: all three were accidentally banged only one broke. Only a first EP step. ?

3. CLIC Meeting 21/08/2001G. Arnau Izquierdo EST/SM3 As Electrical Discharge Machined.  Severe surface cracking.  Cracks follow well defined crystallographic directions.  Flakes 35µm deep. 400µm 50x

4. CLIC Meeting 21/08/2001G. Arnau Izquierdo EST/SM4 As Electrical Discharge Machined. 20µm 100µm 1000x 200x

5. CLIC Meeting 21/08/2001G. Arnau Izquierdo EST/SM5 After grinding  Cracks are no apparent.  Similar to Plansee. 20µm 1000x

6. CLIC Meeting 21/08/2001G. Arnau Izquierdo EST/SM6 After Electropolishing  Good smoothens  Electrolyte agitation problem  Traces of cracks 400µm 50x

7. CLIC Meeting 21/08/2001G. Arnau Izquierdo EST/SM7 Flueckiger Before Electropolishing (2/2) 20µm 100µm 1000x 200x

8. CLIC Meeting 21/08/2001G. Arnau Izquierdo EST/SM8 Conclusions.  The effect of Electrical Discharge Machining is worst than for polycrystalline tungsten.  Intense EP could be needed to get a smooth surface.  EDM parameters can be further improved.  Grinding is feasible. The feasibility of drilling the hole is to be checked.  Good smoothness after EP of the ground surface. First test to be improved.