3D Modelling Problems

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3D Modelling Problems

Postby dakmonf » Tue Nov 29, 2016 5:31 pm

This is very frustrating and I have tried to correct in multiple ways, however whenever I carve a 3d dish model there is some height discrepancies in the model. The preview looks perfect (attached), yet the actual carving does not. The border laurel leaf has portions that do not go as deep as they should and the starting z height is higher than it should be for approx. 2.5 inches and then it drops to the correct height. This is very repeatable in different models (dish). I do a roughing pass with a .5 endmill and a finishing with a .25 ball nose at 7% stepover. If I slow the speed down the issues are not resolved. I do not necessarily want to have to change out my z axis however if that would rectify the problems I will do so.

If anyone can provide any insight into the possible issues I would be very grateful.

Greg
Attachments
Barrel Head.jpg
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Re: 3D Modelling Problems

Postby Rcnewcomb » Tue Nov 29, 2016 5:54 pm

If the preview looks correct then you are dealing with a machine issue. Check the z-axis movement for anything that is binding or loose.
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Re: 3D Modelling Problems

Postby dakmonf » Tue Nov 29, 2016 5:58 pm

Randall; That is certainly sensible however would this be repeatable in the same areas of different models.

Greg
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Re: 3D Modelling Problems

Postby Rcnewcomb » Tue Nov 29, 2016 6:22 pm

A few questions to help debug:
1. What post-processor are you using?
2. Does the problem show up only on 3D work?
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Re: 3D Modelling Problems

Postby dakmonf » Tue Nov 29, 2016 6:38 pm

I am using Mach 2 3 arcs inch and yes it only appears in 3d work, seems to be specific to dishes.

Greg
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Re: 3D Modelling Problems

Postby Rcnewcomb » Tue Nov 29, 2016 7:43 pm

has portions that do not go as deep as they should and the starting z height is higher than it should be for approx. 2.5 inches and then it drops to the correct height

I do a roughing pass with a .5 endmill and a finishing with a .25 ball nose at 7% stepover.

Is the height discrepancy evident on the roughing pass too?
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Re: 3D Modelling Problems

Postby dakmonf » Tue Nov 29, 2016 8:04 pm

Randall;

Yes, the height seems to follow the same path. Would this possibly have something to do with the placement of the zero plane (although I have tried placing at diff. positions in the modelling tree with same results).

Greg
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Re: 3D Modelling Problems

Postby Rcnewcomb » Tue Nov 29, 2016 8:31 pm

If the issue were with the zero place it would:
a) show up in the preview
b) be evident in the entire project

A few more questions:
1. What are the values for Z1 and Z2 in your material setup page?
2. What is your Z feedrate?
3. What material are you cutting? Hardwood, plywood, MFD, foam, etc.
4. Are you always locating your material in the same spot on the table? If you always put your material in the lower left, have you tried putting the material in the center or upper right of your table?
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Re: 3D Modelling Problems

Postby dakmonf » Tue Nov 29, 2016 8:47 pm

Randall;

Z1 is .2 inches, z2 is .2 inches. The plunge rate is at 30 inch per min. I have only used hardwood for models to this point and yes I have positioned the parts on different parts of the table although never too far from my position.

Greg
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Re: 3D Modelling Problems

Postby Rcnewcomb » Tue Nov 29, 2016 9:06 pm

Can you post a photo of an item that shows the problem?
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Re: 3D Modelling Problems

Postby dakmonf » Tue Nov 29, 2016 9:34 pm

I hope that these pics are clear enough to visualize the issue. In the first pic the diff in height was after the finish pass was done. In the second pic it is not too evident but there is an ellipse in the middle that has had the end cut straight instead of curved, this happened on both ends of the ellipse. I should have also noted before that even though I set the gap above model to 0, there was a z drop on the top of the surface at the very beginning of the file.
Attachments
1.jpg
2.JPG
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Re: 3D Modelling Problems

Postby Rcnewcomb » Tue Nov 29, 2016 10:27 pm

Just to cover the bases, can you post the first 25 or 50 lines of the cut file?
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Re: 3D Modelling Problems

Postby dakmonf » Tue Nov 29, 2016 10:52 pm

I hope this is what you wanted. I believe that the initial portion is the correct depth since I specified a 0 gap above the model in the setup. Where the height drops in the first pic is where I believe the error occurs. I do not know how many lines of code this is along the file.

( 3D Roughing 2 )
( File created: Tuesday, November 29, 2016 - 02:44 PM)
( for Mach2/3 from Vectric )
( Material Size)
( X= 35.000, Y= 20.000, Z= 2.000)
()
(Toolpaths used in this file:)
(3D Roughing 2)
(Tools used in this file: )
(1 = End Mill {0.5 inch})
N100G00G20G17G90G40G49G80
N110G70G91.1
N120T1M06
N130 (End Mill {0.5 inch})
N140G00G43Z0.8000H1
N150S12000M03
N160(Toolpath:- 3D Roughing 2)
N170()
N180G94
N190X0.0000Y0.0000F100.0
N200G00X14.3595Y1.6691Z0.2000
N210G1Z-0.1500F30.0
N220G1X20.6405F100.0
N230G1X20.9179Y1.7009
N240G1X21.1392Y1.7282
N250G1X21.3464Y1.7555
N260G1X21.5557Y1.7846
N270G1X21.7610Y1.8148
N280G1X21.9717Y1.8475
N290G1X22.2008Y1.8850
N300G1X22.4932Y1.9358
N310G1X22.6808Y1.9703
N320G1X12.3192
N330G1X12.0954Y2.0133
N340G1X11.8951Y2.0535
N350G1X11.6988Y2.0945
N360G1X11.5037Y2.1369
N370G1X11.3034Y2.1821
N380G1X11.0918Y2.2317
N390G1X10.9284Y2.2715
N400G1X24.0716
N410G1X24.2888Y2.3261
N420G1X24.5535Y2.3956
N430G1X24.7591Y2.4520
N440G1X24.9503Y2.5062
N450G1X25.1332Y2.5597
N460G1X25.1770Y2.5727
N470G1X9.8230
N480G1X9.5598Y2.6532
N490G1X9.3659Y2.7148
N500G1X9.1817Y2.7752
N510G1X9.0054Y2.8347
N520G1X8.8917Y2.8739
N530G1X26.1083
N540G1X26.3117Y2.9460
N550G1X26.4895Y3.0111
N560G1X26.6563Y3.0737
N570G1X26.8250Y3.1388
N580G1X26.9174Y3.1751
N590G1X8.0826
N600G1X7.8793Y3.2572
N610G1X7.7094Y3.3278
N620G1X7.5473Y3.3970
N630G1X7.3908Y3.4655
N640G1X7.3665Y3.4763
N650G1X27.6335
N660G1X27.8173Y3.5592
N670G1X28.0274Y3.6572
N680G1X28.1934Y3.7371
N690G1X28.2760Y3.7775
N700G1X6.7240
N710G1X6.5262Y3.8769
N720G1X6.3717Y3.9569
N730G1X6.2310Y4.0315
N740G1X6.1434Y4.0787
N750G1X28.8566
N760G1X29.0338Y4.1769
N770G1X29.1768Y4.2583
N780G1X29.3156Y4.3393
N790G1X29.3842Y4.3799
N800G1X5.6158
N810G1X5.4396Y4.4871
N820G1X5.3006Y4.5741
N830G1X5.1735Y4.6557
N840G1X5.1345Y4.6811
N850G1X12.6881
N860G1X12.6947
N870G1X12.7079
N880G1X12.7145
N890G1X12.7344
N900G1X12.7410
N910G1X12.7542
N920G1X12.7608
N930G1X12.7939
N940G1X12.8138
N950G1X12.8270
N960G1X12.8534
N970G1X12.8799
N980G1X12.8931
N990G1X12.9196
N1000G1X12.9394
N1010G1X12.9593
N1020G1X12.9725
N1030G1X12.9990
N1040G1X13.0254
N1050G1X13.0849
N1060G1X13.1246
N1070G1X13.1577
N1080G1X13.2040
N1090G1X13.2238
N1100G1X13.2503
N1110G1X13.2701
N1120G1X13.3363
N1130G1X13.3892
N1140G1X13.4157
N1150G1X13.4553
N1160G1X13.4818
N1170G1X13.5347
N1180G1X13.5479
N1190G1X13.5678
N1200G1X13.6207
N1210G1X13.7464
N1220G1X13.7861
N1230G1X13.8720
N1240G1X13.8853
N1250G1X13.9051
N1260G1X13.9183
N1270G1X14.0572
N1280G1X14.0705
N1290G1X14.0969
N1300G1X14.1168
N1310G1X14.1300
N1320G1X14.2491
N1330G1X14.2689
N1340G1X14.2954
N1350G1X14.3284
N1360G1X14.3483
N1370G1X14.4607
N1380G1X14.4806
N1390G1X14.5004
N1400G1X14.5269
N1410G1X14.5335
N1420G1X14.6790
N1430G1X14.6988
N1440G1X14.8642
N1450G1X14.9237
N1460G1X14.9766
N1470G1X15.0891
dakmonf
 
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Re: 3D Modelling Problems

Postby Rcnewcomb » Tue Nov 29, 2016 11:46 pm

I should have also noted before that even though I set the gap above model to 0, there was a z drop on the top of the surface at the very beginning of the file.



Let me ask for others with more G code experience to verify the Z move

Code: Select all
N200G00X14.3595Y1.6691Z0.2000
N210G1Z-0.1500F30.0
N220G1X20.6405F100.0
N230G1X20.9179Y1.7009
N240G1X21.1392Y1.7282
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Re: 3D Modelling Problems

Postby dakmonf » Tue Nov 29, 2016 11:56 pm

I do believe that at the very beginning the file is correct. Later, as you see in the pic. it drops for no apparent reason. This is not the only error I am seeing however it is the most prominent.

Again thank-you for your time.


Greg
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