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Lee Roberts
14-10-2008, 02:58 AM
Easily holds thin material for machining and easy repetitive ability.

http://www.mycncuk.com/images/dump/a_clampbar1.gif

http://www.mycncuk.com/images/dump/a_clampbar3.gif

http://www.mycncuk.com/images/dump/a_clamptablesetup.gif

Holding down thin sheet material can be quite tricky. Multiple clamps can be used but they are time consuming to setup and quite often get in the way while machining. If you need to repeat the operation multiple times you are more likely to introducing errors with positioning. The Clamptable is simply a block of 12 mm thick aluminum with threaded holes in a 20 mm grid and fixing holes to bolt the unit to the milling machine bed. I have chosen a size of 120 X 200 mm but could easily be made larger or smaller as desired.

The other part of the table consists of the clamp bars. There are two types, a fixed bar and an adjustable slide bar.

By using two fixed bars at right angles to give a fixed reference point and an adjustable slide bar on the opposite edge, you can easily repeat work over and over. There are two Clamp table nc files to drill the hole matrix. It is recommended that you first use a 2.5mm center drill drilling to a depth that will open up the ends of the holes slightly. The will help in tapping the holes and prevent raising of metal on the block surface. The second nc file will drill fully through the block. The third file will machine the ends and slots. You can open up the extra end holes manually by hand if required.

The clamp bars are made from 25 mm or 1” X 1/4 material for the fixed bars and 32 mm or 1 1/4” X 1/4 for the adjustable clamps. Three edges of the bar are stepped in 1 mm increments allowing for different material thickness adjustment.

Lee Roberts
14-10-2008, 03:01 AM
Table code files

These files are saved as text files and have been hand written for maximum performance. Rename them to a nc format required.

These files were updated on 31/8/07

Drill File 1

N10 (Clamptable drill file 1)
N20 ( CRH ELECTRONICS DESIGN )
N30 (START POINT BOTTOM LEFT CORNER)
N40 (modified V1.1 32/8/07)
N50 (2.5mm Centre drill set to 3mm clearance)
N60 G0 G49 G40 G17 G80 G50 G90
N70 M6 T4
N80 G21 (mm)
N90 M03 S2000
N100 G00 G43 H4 Z3
N110 G00 X0 Y0
N120 G91
N130 G83 X30 Y10 Z-5 Q2 R2 F50
N140 G91 X20 Y0 L7
N150 G83 X0 Y20 Z-5 Q2 R2 F50
N160 G91 X-20 Y0 L7
N170 G83 X0 Y20 Z-5 Q2 R2 F50
N180 G91 X20 Y0 L7
N190 G83 X0 Y20 Z-5 Q2 R2 F50
N200 G91 X-20 Y0 L7
N210 G83 X0 Y20 Z-5 Q2 R2 F50
N220 G91 X20 Y0 L7
N230 G83 X0 Y20 Z-5 Q2 R2 F50
N240 G91 X-20 Y0 L7
N250 G90
N260 G83 X10 Y20 Z-5 Q2 R2 F50
N270 G83 X10 Y100 Z-5 Q2 R2 F50
N280 G83 X190 Y100 Z-5 Q2 R2 F50
N290 G83 X190 Y20 Z-5 Q2 R2 F50
N300 G90
N310 G00 X0 Y0 Z3
N320 M5 M9
N330 G90
N340 M30
N350


Drill File 2

,

Milling profile

%
N10 (CLAMP TABLE PROFILE MACHINING / CRH Electronics Design)
N15 (Revised 6/9/07)
N20 G90
N30 M06 T01
N40 G21 (metric)
N50 M03 S1200
N60 G0 Z3 (clearance height)
N70 G00 X0.0 Y0.0 (Start point)
N80 G0 X-6 Y-4
N90 G1 Z-1.5 F100
N100 G17
N110 M98 P1 L5 (call sub)
N130 G90 G0 X-6 Y-4
N140 G1 Z-3
N150 M98 P1 L5 (call sub)
N160 G90 G0 X-6 Y-4
N170 G1 Z-4.5
N180 M98 P1 L5 (call sub)
N190 G90 G0 X-6 Y-4
N200 G1 Z-6
N250 M98 P1 L5 (call sub)
N260 G90 G0 z3
N290 G0 X206.0 Y-4 (Start point)
N300 G1 Z-1.5 F100
N310 G17 G91
N320 M98 P2 L5 (call sub)
N330 G90 G0 X206.0 Y-4
N340 G1 Z-3
N350 M98 P2 L5 (call sub)
N360 G90 G0 X206.0 Y-4
N370 G1 Z-4.5
N380 M98 P2 L5 (call sub)
N390 G90 G0 X204.0 Y-4
N400 G1 Z-6
N410 M98 P2 L5 (call sub)

N480 G90 G0 z3 (start slots)
N490 G0 Y60 X204
N500 G91
N510 M98 P3 L6 (call sub)
N520 G90
N530 G0 Z3
N540 G0 X-6
N550 G1 Z-6
N560 G91
N570 M98 P4 L6 (call sub)
N580 G90
N590 G0 Z3.0
N600 G0 X0 Y0 (back to start)
N610 M30
N620 (end)
O1 (Y path sub)
N630 G91
N635 G1 X2
N640 G1 Y128
N650 G1 X2
N660 G1 Y-128

N680 M99
O2 (Y path sub)
N690 G91
N695 G1 X-2
N700 G1 Y128
N710 G1 X-2
N720 G1 Y-128

N740 M99
O3 (right hand slot)
N750 G1 Z-1
N760 G1 X-14
N770 G04 P1000
N780 G1 X14
N790 M99
O4 (left hand slot)
N800 G1 Z-1
N810 G1 X14
N820 G04 P1000
N830 G1 X-14
N840 M99
%

Lee Roberts
14-10-2008, 03:03 AM
Clamp bar files

The two files below are for the fixed and slotted bars.

File A will drill the holes and File B is to cut the five slots. The 1 mm, 2 mm and 3 mm step lips can be done manually or cut to different depths for your own requirements.

Hole File A

N10 (Clamptable BAR file 3)
N20 ( CRH ELECTRONICS DESIGN 1/10/07)
N30 (START POINT BOTTOM LEFT CORNER)
N40 (T4 2.5mm Centre drill set to 3mm clearance)
N50 G0 G49 G40 G17 G80 G50 G90
N60 M6 T4
N70 G21 (mm)
N80 M03 S2000
N90 G00 Z3 Y0 X0
N95 G43 H4
N100 G91
N110 G83 X10 Y12.5 Z-5 Q2 R1 F50
N120 G91 X20 Y0 L4
N130 G90 G0 z3
N135 G0 x0 y0

N140 M6 T5
N150 (T5 3MM TWIST DRILL)
N160 G00 G43 H4 Z3
N170 G91
N180 G83 X10 Y12.5 Z-7 Q1.5 R1 F50
N190 G91 X20 Y0 L4
N195 G90 G0 z3
N200 G0 x0 y0
N210 M5 M9
N220 G90
N230 M30
N240


Slot File B

%
N10 (CLAMP TABLE SLOT BARS FILE 4)
N20 ( CRH Electronics Design)
N30 (Use 3mm slot drill)
N40 (Bottom left reference point)
N50 G90
N60 M06 T01
N70 G21 (metric)
N80 M03 S1200
N90 G0 Z3 Y0 X0 (clearance height)
N100
N110 G90 (start slots)
N120 G0 Y7 X10
N130 G0 Z0
N140 G91
N150 M98 P3 L3 (call sub)
N160 G90 G0 Z3
N170 G0 Y7 X30
N180 G0 Z0
N190 G91
N200 M98 P3 L3 (call sub)
N210 G90 G0 Z3
N220 G0 Y7 X50
N230 G0 Z0
N240 G91
N250 M98 P3 L3 (call sub)
N260 G90 G0 Z3
N270 G0 Y7 X70
N280 G0 Z0
N290 G91
N300 M98 P3 L3 (call sub)
N310 G90 G0 Z3
N320 G0 Y7 X90
N330 G0 Z0
N340 G91
N350 M98 P3 L3 (call sub)
N360 G90
N370 G0 Z3
N390 G0 X0 Y0 (back to start)
N400 M30
N410 (end)
N420
O3 (right hand slot)
N10 G1 Z-1.1 F50
N20 G04 P2000 (DWELL 2 SECONDS)
N30
N40 G1 Y18
N50 G1 Z-1.1
N60 G04 P2000
N70 G1 Y-18
N80 M99
N90
%


Short video of cutting the slot bar

http://uk.youtube.com/watch?v=2oNGUXZjq3E

Provided by www.diycnc.co.uk (http://www.diycnc.co.uk)