Girders fabrication: Difficulties to achieve tolerances and machining process
Igor Madariaga (ESS-Bilbao)13 September 2011
DTL mini-workshop, CERN
Outline
1. Introduction to DTL
2. Girder´s properties
3. Girder´s new machining process
4. Improvements of the new machining process
Introduction to DTL
• Main Parts of the DTL– Drift tubes – Tank– Girder
Introduction to DTL
• Parts– Drift tubes – Tank– Girder
• Drift tubes
Introduction to DTL
• Parts– Drift tubes – Tank– Girder
• Tank
Introduction to DTL
• Girder
Spend time machining the girder avoid post - alignments
Girder´s properties
• Girder main functions:– Fix the position of the DTs with high precision
• Material– Aluminum EN AW-5083 H111
• Dimensions– 1924 x 150 x 177 mm
• 2 machining process– The old one does not achieve the
tolerances between critical holes
Girder´s new machining process
• Main parts of the process
– Rough milling
• Leaving 5 – 6 extra mm for each dimension
– Stress releve
• Thermal treatment
– Pre finish
– Finish
Girder´s new machining process
• Rough milling– Machine: Centro mecanizado Soraluce– Be sure not to introduce any linear or torsional deformation
Test with dial indicators
– Avoid heating of the milling zone – Use 4 supports and 4 clamps
Large quantity of coolant
Girder´s new machining process
• Definition oh holes and faces
Stamp holesTop face
Cooling holesLeft/right face
Fit into the tank (Girder key)Bottom face
Girder key
Hoist points
Girder´s new machining process
• Rough milling– Square the part to obtain parallel faces– Drill stemp and cooling holes (ø50 and ø40)– Mill girder key(80)
Old machining process
Girder´s new machining process
• Pre finish– Machine: Mandrinadora SACEM-530
• Precision: +/- 0,01mm– Control room temperature +/- 0,5° C to avoid thermal dilatations.– Be sure not to introduce any linear or torsional deformation
Test with dial indicators– Use 3 supports and 3 clamping points (L/5 and in the middle)
Girder´s new machining process
• 3 supports and 3 clamping points supporting the part in top face
– Finish-mill ø35 pocket– Tap M-12 screw holes– Finish-drill ø40 holes cooling holes– Pre-Finish face B
Old machining process
First low tolerance dimensionsAfter high tolerance dimensions
Top face
Right face
Hoist holes
Girder´s new machining process
• Turn table 180 °
– Finish-mill ø35 pocket
– Tap M-12 screw holes
– Finish-drill ø40 holes cooling holes
– Pre-Finish face C
Top face
Left face
Hoist holes
Girder´s new machining process
• 3 supports and 3 clamping points supporting the part in right face
– Rough-mill 15k6 to 15,5mm– Rough-mill 80h6 to 80,5mm– Finish-drill ø12,5 holes – Tap hoist drills M-12– Finish-boring ø49,5 – Finish-boring 50 H7– Pre-finish face A Old machining
process
Girder key
Stamp holes
Right face
Bottom face
Hoist holes
Girder´s new machining process
• Turn table 180 °
– Finish-mill ø42 pocket– Rough-drill ø10H7 to ø8– Finish-drill ø14 holes – Finish-mill ø35 pocket– Tap M-12 screw holes– Finish-mill ø70– Finish-boring 50 H7– Pre-Finish face D– Insert the bushes
Old machining processStamp
holes
Right face
Top face
Hoist holes
Girder´s new machining process
• Finish– Machine: DIXI 5S– Dimensions:
• Axis X 2m• Axis Y 2m• Axis Z 1m
– Precision:• Flatness 0,002 – 0,003 mm / 2 m• 0,001 mm distance between holes• Turn 0,0002 °
Girder´s new machining process
• Finish– Control of the temperature of the room +/- 0,25° C to avoid
thermal dilatations.– Be sure not to introduce any linear or torsional deformation
Test with dial indicators
– Use 3 supports and 3 clamping points (L/5 and in the middle)
Girder´s new machining process
• 3 supports and 3 clamping points supporting the part in top face
– Finish-mill face right face to high tolerance Reference face• 3 supports and 3 clamping points supporting the part in right face
– Finish-boring ø10 H7– Finish-mill face D
Top face
Right face
Right face
Top face
Girder´s new machining process
• Turn table 180
– Finish-mill 80 h6
– Finish mill 15h6
– Finish-boring 40 H6 and 39,8 H6
Girder fit
Stamp holes
Right face
Bottom face
Improvements of the new machining process
–Better machine, with better tolerances–Temperature control:
• Better control of the room´s temperature• Better temperature control in the milling zone
Really important to avoid thermal dilatations–Different machining process
• Don´t leave the small drills for the final
Girders fabrication: Difficulties to achieve tolerances and machining process
Igor Madariaga (ESS-Bilbao)13 September 2011
DTL mini-workshop, CERN