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