[elmor fudd]

Although im new to using cad im not new to cnc programming but i have decided that nows the time to start using it due to needing the extra time although i have always enjoyed working the programs out myself.
I have now started to use Bobcad but today i have hit a brick wall even though i have found the program very easy to use and to be honest i have very much enjoyed using it until now.
I have drawn an elips of 50.4mm wide by 30mm high and hit the program button and genertaed the program with no problem what so ever until i have come to run it on mach 3

The mach software shows that it has programed it with a few X and Y moves with no I or J following it so it wont run the program for some reason.

Can anyone hlp with this and tell me why bobcad has done this or is it a problem with mach 3, bobcad,myself or a combination of all 3 that have got this simple program wrong?

I would very much appreciate some help with this guys as now i have started using cad i have found myself really enjoying it but its getting me to the point where Im about to pull whats left of my hair out over this.

Heres the program that bobcad generated for an inside elips of 50.4mm wide by 30mm high using a 5mm end mill with anti clockwise move and G41 offset.

Thanks
%
G00G90G21G54X0.Y0.
T1M06 (5MM END MILL)
G43H01Z1.
G17G41P2.5
G00X-34.7731Y-4.8343
G01Z-2.F40
G03X-48.9638I-8.2783J-40.4892F100
G03X-58.0957Y-6.9776I6.8545J-33.1986F100
G03X-51.3892I5.8674J-40.59F100
G03X-63.5176Y-10.2804I9.3961J-21.5263F100
X-66.9488Y-14.3285I9.0997J-11.191
X-67.5655Y-22.3618I8.1912J-4.6692
G03X-63.5324Y-27.7071I12.4868J7.1831F100
G03X-66.9189Y-23.7233I8.967J3.4249F100
G03X-58.1342Y-31.005I14.8048J18.1669F100
X-51.3269Y-33.1657I13.5888J31.0081
X-37.1362I8.2783J40.4892
G03X-28.0043Y-31.0224I-6.8545J33.1986F100
X-37.1362Y-33.5781
G03X-34.7108I-5.8674J40.59F100
X-28.0043Y-31.0224
G03X-22.5824Y-27.7196I-9.3961J21.5263F100
X-19.1905Y-23.74I-9.0997J11.191
X-18.5327Y-22.3571
G03X-19.1456Y-14.3389I-8.8054J3.3594F100
Y-23.74
G03X-18.5327Y-22.3571I-8.3454J4.8179F100
X-19.1456Y-14.3389
G03X-22.5677Y-10.2928I-12.5226J-7.1212F100
X-27.9658Y-6.995I-14.8048J-18.167
X-34.7731Y-4.8343I-13.5888J-31.0081
G00Z1.
G40
G00G54X1.Y1.
G54X0.Y0.
M30

[Mike Stevenson]

elmor fudd,

Unfortunately, I must tell you that this NC code is no good. I will show you a Vericut verification video of your code in my next post.

[Mike Stevenson]

Elmer,

Here is the Vericut verification video of your code:

[ame="http://www.youtube.com/watch?v=KOReKOyR1cE"]YouTube - cnczone ellipse part[/ame]

You can plainly see that this NC code is your problem.

I have attached the txt I actually ran through the Vericut processor:

[elmor fudd]

Elmer,

Here is the Vericut verification video of your code:

YouTube - cnczone ellipse part

You can plainly see that this NC code is your problem.

I have attached the txt I actually ran through the Vericut processor:

Thanks for that mate but i know its no good hence why i asked the question about bobcad comming up with that program for an elips at the stated size in my post because thats what it generated and with me being new to cad i wasnt sure if it was me thats done something wrong or if their was a glitch in the bobcad sofware?

[Mike Stevenson]

Now you know that the bobcad is messing you up, not MACH3.

[Kiwi]

Here is the code for a ellipse of 50.4mm wide by 30mm high with left comp. that V20 generated. I had no problems. (No lead in or exit)
G00 X24.5659 Y-3.3575
G01 X24.5659 Y-3.3575 Z0. F50
G41 G03 X23.9524 Y4.6603 I-8.7883 J3.3599 F400
G03 X20.5238 Y8.7066 I-12.5229 J-7.1355
G03 X15.1148 Y12.0047 I-14.8224 J-18.2247
G03 X8.2937 Y14.1656 I-13.6132 J-31.1251
G03 X-5.9257 Y14.5781 I-8.2951 J-40.6517
G03 X-8.356 Y14.1528 I5.8791 J-40.7506
G03 X-15.0761 Y12.0222 I6.8651 J-33.3164
G03 X-20.509 Y8.7191 I9.4029 J-21.585
G03 X-23.9468 Y4.6706 I9.0935 J-11.2057
G03 X-24.564 Y-3.3626 I8.1735 J-4.6683
G03 X-23.9166 Y-4.7227 I8.951 J3.4263
G03 X-20.5239 Y-8.7065 I12.4869 J7.1976
G03 X-15.1148 Y-12.0047 I14.8225 J18.2246
G03 X-8.2937 Y-14.1656 I13.6132 J31.1251
G03 X5.9257 Y-14.5781 I8.2951 J40.6517
G03 X8.356 Y-14.1528 I-5.8791 J40.7506
G03 X15.0761 Y-12.0222 I-6.8651 J33.3164
G03 X20.509 Y-8.7191 I-9.4029 J21.585
G03 X23.9073 Y-4.7392 I-9.0935 J11.2057
G40 G03 X24.5659 Y-3.3575 I-8.3284 J4.8175
G00 X24.5659 Y-3.3575 Z10.

[Mike Stevenson]

Kiwi,

G41 on a G03 move? Wow.

Edit: I am being told this ellipse file is no problem with older versions of BC.

[Kiwi]

...G41 on a G03 move? Wow.

You're right Mike, should have had a straight path to enable compensation.

[moldmker]

Here's v22 code but I was using a Fanuc6M post.
Origin in center of ellipse.
There are some guys in the Bobcad forum that are successfully using v22 for Mach.
Maybe post a question there?
Good luck,
moldmker

%
O100(TEST.NC)
(FANUC POST)
(JOB 1 CONTOUR)
(TOOL #1 5.0000 ENDMILL ROUGH)
G0G17G40G80G90G28 Z0
T1M6
S950M3
M8
G54
G00X-13.0792Y7.4383
G43Z2.54H1D11
G01Z-12.7F57.961
G41X-15.0761Y12.0222F96.602
G03X-20.509Y8.7191I9.4029J-21.5851
G03X-23.9468Y4.6706I9.0934J-11.2057
G03X-24.564Y-3.3626I8.1735J-4.6683
G03X-23.9166Y-4.7227I8.951J3.4263
G03X-20.5239Y-8.7065I12.4869J7.1976
G03X-15.1148Y-12.0047I14.8225J18.2246
G03X-8.2937Y-14.1656I13.6131J31.1251
G03X5.9257Y-14.5781I8.2951J40.6517
G03X8.356Y-14.1528I-5.8791J40.7506
G03X15.0761Y-12.0222I-6.8651J33.3164
G03X20.509Y-8.7191I-9.4029J21.5851
G03X23.9073Y-4.7392I-9.0934J11.2057
G03X24.5659Y-3.3575I-8.3285J4.8176
G03X23.9524Y4.6603I-8.7883J3.3599
G03X20.5238Y8.7066I-12.5229J-7.1355
G03X15.1148Y12.0047I-14.8224J-18.2247
G03X8.2937Y14.1656I-13.6131J-31.1251
G03X-5.9257Y14.5781I-8.2951J-40.6517
G03X-8.356Y14.1528I5.8791J-40.7506
G03X-15.0761Y12.0222I6.8651J-33.3164
G40G01X-13.0792Y7.4383
G00Z2.54
M9
M5
G0G90G49Z0
G28Z0
M30

[Mike Stevenson]

moldmker,

You code is okay. I only had to add the G21 at the start.

[Mike Stevenson]

Kiwi,

Your code is ok if you add the inch/mm code, plus tool change, initial move, rpm, and height offset at the begining and you delete the G41 on the G3 move as you can see in Pic1. Pic2 shows your code with the G41 left on the G3 line in a MACH3 machine simulation. Note the D flat on the right hand side.

[Kiwi]

Your code is ok if you add the inch/mm code, plus tool change, initial move, rpm, and height offset at the begining........

I was trying to help with the ellipse profile. I could see elmor had the other details sorted.

[elmor fudd]

Kiwi,

Your code is ok if you add the inch/mm code, plus tool change, initial move, rpm, and height offset at the begining and you delete the G41 on the G3 move as you can see in Pic1. Pic2 shows your code with the G41 left on the G3 line in a MACH3 machine simulation. Note the D flat on the left hand side.

HA ha, youv hit upon the first problem i came across which promted me to re do the program.
the first program i did was right for some of the elips but then as it got to the end it did a funny tuen and gave me a flat spot a little like you got but in a differant place.
When i redid the program it gave me the above program i posted for some reason
Now it seems to me that mach 3 doesnt like using the g41 or g42 offset codes or is this just me?

I might have a go at programming the elips exact to compenstate for the tool in the size of the elips instead of using the offset values and see if it irons the glich out so fingers crossed

Thanks for the help guys its much appreciated and if anyone else has any input that would be great to

[moldmker]

Elmor,

You can let the software offset the path, as well.

In the Patterns window, when you use the No Offset L/R buttons the toolpath is generated directly on your geometry and the needed G41/G42 is added to G-code.

If you use Offset R/L the toolpath is generated offset from your geometry by 1/2 cutter dia. plus any side allowance. This is a precompensated toolpath.
However, depending on your post-processor, it may also add G41/G42 as a "wear offset"
This can be changed with the MillPostEditor.

Attached is shot of Patterns window.

Good luck
moldmker

[elmor fudd]

Now you know that the bobcad is messing you up, not MACH3.

Your not wrong mate

pm on way

[Mike Stevenson]

Jay (elmer_fudd),

Based on the IGS file you sent me this is my take on your part:

%
O0001(BRACKET_DRAWING_DRAWING)
G21
G0G17G40G49G80G90
(5.0 MM FLAT END MILL)
T1M6
G0G90X-39.878Y-10.503S2000M3
G43H1Z100.M8
Z10.
G1Z-3.F1.8
G41D21X-39.889Y-8.503F20.
G3X-41.901Y-6.515R2.
G1X-44.623Y-6.53
G3X-50.873Y-7.295R38.52
X-57.073Y-9.261R31.469
X-61.923Y-12.21R21.052
X-64.736Y-15.496R12.116
X-64.767Y-22.446R6.97
X-61.992Y-25.737R12.134
X-57.125Y-28.716R21.146
X-50.833Y-30.714R31.369
X-35.227Y-30.705R38.819
X-29.027Y-28.739R31.469
X-24.177Y-25.79R21.052
X-20.891Y-21.516R11.345
X-21.317Y-15.585R6.954
X-24.11Y-12.261R12.083
X-28.975Y-9.285R21.134
X-35.267Y-7.286R31.369
X-41.901Y-6.515R38.961
X-43.99Y-8.421R2.
G1G40X-44.081Y-10.419
G0Z100.
X2.5Y2.5
Z10.
G1Z-3.
G41D21Y-26.9
X-13.469
G3X-14.791Y-27.119R3.65
X-16.45Y-28.37R3.875
G1X-17.706Y-29.797
X-18.943Y-30.948
X-20.909Y-32.475
X-22.998Y-33.821
X-25.517Y-35.121
X-28.139Y-36.203
X-30.864Y-37.095
G2X-36.182Y-38.239R42.073
G1X-39.284Y-38.601
X-42.403Y-38.75
X-45.521Y-38.688
X-48.625Y-38.416
X-51.671Y-37.938
G2X-55.45Y-37.033R40.487
G1X-58.17Y-36.124
X-60.671Y-35.082
X-62.874Y-33.952
X-64.974Y-32.628
X-67.218Y-30.892
X-68.689Y-29.49
X-70.033Y-27.891
X-71.161Y-26.201
G2X-72.385Y-23.63R14.622
G1X-72.877Y-21.927
X-73.145Y-20.123
G3X-73.226Y-17.74R43.298
X-77.693Y-13.85R4.497
G1X-87.9
Y2.5
G40X2.5
G0Z100.M9
M5
G91G28Z0.
G28Y0.
M30
%

Here's the Vericut video:

[ame="http://www.youtube.com/watch?v=lPHYnljEbIQ"]YouTube - cnczone ellipse Michael style[/ame]

[elmor fudd]

Now thats what its supposed to look like
Thanks for your time with this guys and especially Mike.
I have now come to the conclusion that Bobcad was a bad choice.
I did the same program as above but it had glitches galore and didnt look smooth like Mike's program when loaded to mach 3 for some reason even though the program is more or less the same so Bobcad will be gone off my pc by the end of the day.
I havent had chance to do a test cut with mike's to see what the finish is like but i have done a cut with my program from Bobcad and what i seen on the screen on mach 3 i got on the job so if Mike's program does the same it should come out fine.

The one thing that is bugging me is that Bobcad state that they supply their software to NASA and other big companies but i would have thought that they must suffer the same glitches on drawings as i have done which i would have thought un acceptable to these types of companie or is it just a marketing ploy?