## 3D Modelling Problems

**Moderator:** Todd Bailey

### 3D Modelling Problems

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

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

Greg

- Rcnewcomb
- Vectric Wizard
**Posts:**3733**Joined:**Fri Nov 04, 2005 5:54 am**Model of CNC Machine:**GCnC/WinCNC**Location:**San Jose, California, USA-
**Contact:**

### Re: 3D Modelling Problems

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.

- Randall Newcomb

### Re: 3D Modelling Problems

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

Greg

Greg

- Rcnewcomb
- Vectric Wizard
**Posts:**3733**Joined:**Fri Nov 04, 2005 5:54 am**Model of CNC Machine:**GCnC/WinCNC**Location:**San Jose, California, USA-
**Contact:**

### Re: 3D Modelling Problems

A few questions to help debug:

1. What post-processor are you using?

2. Does the problem show up only on 3D work?

1. What post-processor are you using?

2. Does the problem show up only on 3D work?

- Randall Newcomb

### Re: 3D Modelling Problems

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

Greg

Greg

- Rcnewcomb
- Vectric Wizard
**Posts:**3733**Joined:**Fri Nov 04, 2005 5:54 am**Model of CNC Machine:**GCnC/WinCNC**Location:**San Jose, California, USA-
**Contact:**

### Re: 3D Modelling Problems

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?

- Randall Newcomb

### Re: 3D Modelling Problems

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

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

- Rcnewcomb
- Vectric Wizard
**Posts:**3733**Joined:**Fri Nov 04, 2005 5:54 am**Model of CNC Machine:**GCnC/WinCNC**Location:**San Jose, California, USA-
**Contact:**

### Re: 3D Modelling Problems

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?

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?

- Randall Newcomb

### Re: 3D Modelling Problems

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

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

### Re: 3D Modelling Problems

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.

- Rcnewcomb
- Vectric Wizard
**Posts:**3733**Joined:**Fri Nov 04, 2005 5:54 am**Model of CNC Machine:**GCnC/WinCNC**Location:**San Jose, California, USA-
**Contact:**

### Re: 3D Modelling Problems

Just to cover the bases, can you post the first 25 or 50 lines of the cut file?

- Randall Newcomb

### Re: 3D Modelling Problems

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

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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

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N1080G1X13.2040

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N1100G1X13.2503

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N1120G1X13.3363

N1130G1X13.3892

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N1390G1X14.5004

N1400G1X14.5269

N1410G1X14.5335

N1420G1X14.6790

N1430G1X14.6988

N1440G1X14.8642

N1450G1X14.9237

N1460G1X14.9766

N1470G1X15.0891

( 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

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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

- Rcnewcomb
- Vectric Wizard
**Posts:**3733**Joined:**Fri Nov 04, 2005 5:54 am**Model of CNC Machine:**GCnC/WinCNC**Location:**San Jose, California, USA-
**Contact:**

### Re: 3D Modelling Problems

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

- Randall Newcomb

### Re: 3D Modelling Problems

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

Again thank-you for your time.

Greg