Cutting question

[ZigMan]

This was just a simple test. It is done in ArtCam and transfered to Mach3 in .tap format. The 1/8" straight bit needed to plunge 1/4" into the material and make a simple circular cut along the vector. The photo shows the uneven line along the cut circle. This is the starting and finishing point of the cut.

Can anyone tell me why is this happening? It should be a perfect circle.

Thanks

[wetracer]

If you could post the code used to cut the piece it would help. It can then be determined if the problem is in the programming or in the machine.

[Boots]

Being as it is at your starting and ending points I would say it is most likely your cutter radius. It should be turning on your radius comp. prior to going into the material and turning off comp. after exiting the material.
That's my guess.

[ALLtra Mach]

Another guess is that you're not overlapping your lead in/out and using a circular or angled lead in/out .
But without the code to look at we're all really just guessing

[ZigMan]

here's the code:

T1M6
G0Z0.2000
G0X0.0000Y0.0000S15000M3
G0X0.7500Y1.5000Z0.2000
G1Z-0.1250F15.0
G1X0.7516Y1.5492F30.0
X0.7565Y1.5991
X0.7650Y1.6492
X0.7769Y1.6994
X0.7925Y1.7491
X0.8117Y1.7981
X0.8344Y1.8459
X0.8606Y1.8921
X0.8900Y1.9365
X0.9224Y1.9786
X0.9575Y2.0181
X0.9952Y2.0548
X1.0349Y2.0886
X1.0764Y2.1191
X1.1194Y2.1464
X1.1634Y2.1704
X1.2081Y2.1911
X1.2545Y2.2089
X1.3023Y2.2237
X1.3511Y2.2352
X1.4005Y2.2435
X1.4502Y2.2484
X1.5000Y2.2500
X1.5492Y2.2484
X1.5991Y2.2435
X1.6492Y2.2350
X1.6994Y2.2231
X1.7491Y2.2075
X1.7981Y2.1883
X1.8459Y2.1656
X1.8921Y2.1394
X1.9365Y2.1100
X1.9786Y2.0776
X2.0181Y2.0425
X2.0548Y2.0048
X2.0886Y1.9651
X2.1191Y1.9236
X2.1464Y1.8806
X2.1704Y1.8366
X2.1911Y1.7919
X2.2089Y1.7455
X2.2237Y1.6977
X2.2352Y1.6489
X2.2435Y1.5995
X2.2484Y1.5498
X2.2500Y1.5000
X2.2484Y1.4508
X2.2435Y1.4009
X2.2350Y1.3508
X2.2231Y1.3006
X2.2075Y1.2509
X2.1883Y1.2019
X2.1656Y1.1541
X2.1394Y1.1079
X2.1100Y1.0635
X2.0776Y1.0214
X2.0425Y0.9819
X2.0048Y0.9452
X1.9651Y0.9114
X1.9236Y0.8809
X1.8806Y0.8536
X1.8366Y0.8296
X1.7919Y0.8089
X1.7455Y0.7911
X1.6977Y0.7763
X1.6489Y0.7648
X1.5995Y0.7565
X1.5498Y0.7516
X1.5000Y0.7500
X1.4508Y0.7516
X1.4009Y0.7565
X1.3508Y0.7650
X1.3006Y0.7769
X1.2509Y0.7925
X1.2019Y0.8117
X1.1541Y0.8344
X1.1079Y0.8606
X1.0635Y0.8900
X1.0214Y0.9224
X0.9819Y0.9575
X0.9452Y0.9952
X0.9114Y1.0349
X0.8809Y1.0764
X0.8536Y1.1194
X0.8296Y1.1634
X0.8089Y1.2081
X0.7911Y1.2545
X0.7764Y1.3023
X0.7648Y1.3511
X0.7565Y1.4005
X0.7516Y1.4503
X0.7500Y1.5000
G0Z0.2000
G0X0.0000Y0.0000
G0Z0.2000
G0X0Y0
M30

Boots, I did not understand what you mean by "comp." , you got me lost there.

It looks as if the cutter plunges slightly inside the circle's vector instead on the centerline, then it goes to follow the vector ok but before it finishes it goes back to the starting point.

[ger21]

The code looks OK here. Are you sure the machine isn't flexing when plunging? What kind of machine is this?

[Boots]

Zigman,
Sorry but I thought everyone knew the abreviation for compensation (Comp.) I did run your NC code in my software and it looks like a bunch of straight lines all connected to form a circle about 1.4 inches accross. There is no approach to the cut in the code so I'm not sure how your machine is handling it. But I have to tell my machine the dia. of the tool so it will move off the Radius of the tool and be lined up with the cut line before plunging in. This is the Comp.=Compensation.

[ger21]

Boots. he's not using comp. No G41/G42.

[RICHARD ZASTROW]

Haven't done manual G-code for (secret) years. Should the tool have returned to X0.7516Y1.5492 after X0.7516Y14503 to complete circle? Maybe I'm becoming sen....

Dick Z

[ZigMan]

I have just started with ArtCam and I'm not familiar with it yet. I will look for the comp. settings but I know the program did ask me what tool do I want to use use and I had a 1/8" straight bit set as the tool. And there is a function where the bit follows the vector, I guess it is used for simple centerline engraving.

[rgammage]

Hello All

This looks like a simple HPGL to G code conversion .... most plotters draw 70 straight lines for a circle and this looks 'oh so similar' .... good for systems with no circular interpolation (G41/42). Maybe the option is turned off?

In any event I agree with Gerry something is moving that is not suppose to.

Regards

Richard

[Paul_S]

The code only gives 1/8 plunge depth. Not the 1/4 you said. My guess is the plunge is staight. And the direction of the cut is conventional to the outside and climb to the inside making the cutter pull outward through the cut path. So the start and finish would look to be inside the cut arc.

Depending on cutter flute length and cutter stick out of the holder could affect this.