509,948 active members
3,731 visitors online
Register for free
Login
IndustryArena Forum > CAM Software > MadCAM > Cut quality problem
Page 1 of 3 123
Results 1 to 12 of 31
  1. #1
    Registered
    Join Date
    May 2006
    Posts
    314

    Cut quality problem

    I post this cut quality question on the Mach3 forum. I'm just cutting a simple cam 2.5d profile, it sounds super smooth while cutting but I get slightly wavy and bumpy cuts. This is answer I received, but don't know how to correct this in Rhino or Madcam? Suggestions?

    Check your Gcode - if the curves are comprised of many straight lines then the answer is with your CAD/CAM and it's Post Processor.

    (Vectric, for example, will enable 'curve fit' to replace the many straight lines in an imported dxf and then the final Mach3 post processor will use 'arcs' (G2, G3) for the toolpath).
    Attached Thumbnails Attached Thumbnails 20190920_164051.jpg  

  2. #2
    Community Moderator svenakela's Avatar
    Join Date
    Mar 2004
    Posts
    1659

    Re: Cut quality problem

    There are two things here I would like to discuss. Or, maybe three when I think about it.
    1. Yes, the default Mach3 post is producing small lines representing the arch. There are a few settings you can adjust to make it good. First make sure the mesh settings are set according to the help file. These settings you can save in your normal template files so it is a make-once-always-set thing if done right. There is also a tolerance setting in the Tools Dialog. The lower you set it, the better result (and larger file). With that said, it is very high precision G-code coming out of MadCam. I've done cuts where the room temperature affects the tolerance.

    2. All 2.5D operations can be transposed to G2/G3 in MadCam, but I strongly believe the Mach3 post is still line based. For older machines it produces a smaller file to process and you can gain some serious speed in modern sturdy machines.

    3. BUT, to me this looks like jitter, your machine is simply not beefy enough to cut like this and in worst case you have material building up. You can experiment with cut depth, go shallow and more rounds, keep cooling with alcohol, soap or water mist and make sure to blow off chips. It will probably give you a better result.

    Also, are you using an ALU specific cutter? That can make a hyyuge difference.

  3. #3
    Registered
    Join Date
    May 2006
    Posts
    314
    Mach3 has some conversational programming options. When I do a circle interpolation the cut comes out perfectly smooth. So I'm ruling out machine and cutting bit for now.

    I've played with the mesh settings, cutter tolerances... they help but problem is still there.

    I really think this is a Rhino drawing problem. I'm using a a 2d curve drawing only for the toolpath. Is a curve affected by mesh settings?
    This closed curve is originally imported into Rhino from 3600 cloud points. I then generate closed curve from points. I then rebuild curve to around 100 points.

    Do I need to extrude curve and use the extruded shapes sides for a better toolpath?

    I do remember testing a circle drawn in Rhino, used Madcam and comparing to the conversational cut circle in Mach3. Mach3 was a beautiful cut. From Rhino/madcam same issue as pic in original post.

    I'm missing something in my Rhino and or Madcam settings

    Thank you for your help!

  4. #4

    Join Date
    Aug 2019
    Posts
    295

    Re: Cut quality problem

    What is the cam tolerance you set for the linear motions output? If I set mine at 0.1mm I would get similar results on M3, worst in fact. Although if the motions are set to 0.001mm then the finishes are near perfection (to the naked eye anyway). Likely you'll end up with 10,000+ lines of code at those low tol so set your M3 look-ahead to about 500 and you should be sort-of-okay

  5. #5
    Registered
    Join Date
    May 2006
    Posts
    314
    Quote Originally Posted by Mecanix View Post
    What is the cam tolerance you set for the linear motions output? If I set mine at 0.1mm I would get similar results on M3, worst in fact. Although if the motions are set to 0.001mm then the finishes are near perfection (to the naked eye anyway). Likely you'll end up with 10,000+ lines of code at those low tol so set your M3 look-ahead to about 500 and you should be sort-of-okay
    My M3 look ahead is at 200. I'll try a high number there.

    I don't know what you mean by linear motions output? In my tool cutter tolerance I have it set to .0001" (imperial). I played with this setting. Really didn't seem to make a difference.

    There is a setting to change in machine setup. I'm not by that computer, and I forget what it's called. Is there anything there that would be helpful? There's also 4 separate boxes to check... something 2 toolpaths or 4 toolpaths... what are they for?

  6. #6
    Registered
    Join Date
    May 2006
    Posts
    314

    Re: Cut quality problem

    And do I really want jagged seams checked in Rhino mesh settings

  7. #7

    Join Date
    Aug 2019
    Posts
    295

    Re: Cut quality problem

    Quote Originally Posted by williamsmotower View Post
    I don't know what you mean by linear motions output?
    By means of post processing points, the cam tool should give you the option to set a tolerance for the linear motions (distance between each points it outputs).
    If that option is not available then that's not a CAM, its a SCAM. Need to look at procuring another CAM with an industry focus (pretty standard option with most cam)
    Attached Thumbnails Attached Thumbnails Ops.jpg  

  8. #8
    Registered
    Join Date
    Jan 2018
    Posts
    323

    Re: Cut quality problem

    What finishing speed are you using?
    With my Sieg X2 and a 6mm 4fl cutter it only seems to like 1500rpm, 175mm/min, 0.3mm stepover.
    Backlash won't cause that, it'll only cause a flat spot or line at transitions/ change of direction.

  9. #9
    Registered
    Join Date
    May 2006
    Posts
    314

    Re: Cut quality problem

    Backlash shouldn't be the issue, I do have .001" on each axis, but have backlash compensation on in Mach3. My manual programming yields no issues with backlash. My Madcam post shouldn't turn off backlash compensation?

  10. #10

    Join Date
    Aug 2019
    Posts
    295

    Re: Cut quality problem

    Quote Originally Posted by williamsmotower View Post
    My Madcam post shouldn't turn off backlash compensation?
    Lets have a look at your program/gcode. Your CAM may in fact add both 'counter-backlash' & 'backlash' every now and then, which is what I've been suspecting from the start (tol).
    If you upload that program that'll make it much easier for us to debug remotely

  11. #11
    Registered
    Join Date
    May 2006
    Posts
    314

    Re: Cut quality problem

    Here is the gcode in attachment. I used this to skim the part .002" to see if the cut quality was better. Finish turned out exactly like original

  12. #12
    Registered
    Join Date
    May 2006
    Posts
    314

    Re: Cut quality problem

    are these settings correct?
    Attached Thumbnails Attached Thumbnails madcamoptionsjpg2.jpg  

Page 1 of 3 123

Similar Threads

  1. MAX100 cut quality / nozzle build up problem
    By MrUno in forum Hypertherm Plasma
    Replies: 1
    Last Post: 08-03-2016, 08:15 AM
  2. Old problem - CO2 laser cut quality in Acrylic sheet
    By Nitrous in forum General Laser Engraving / Cutting Machine Discussion
    Replies: 0
    Last Post: 11-08-2015, 05:11 PM
  3. Problem - Making good quality plasma bevel cutting
    By siegfried_74 in forum General Off Topic Discussions
    Replies: 1
    Last Post: 04-26-2015, 01:53 PM
  4. Quality Engineer/Quality manager - MI
    By MachiningJobs in forum Employment Opportunity
    Replies: 0
    Last Post: 04-04-2011, 10:51 PM
  5. Beam quality problem ...
    By smartcut in forum General Laser Engraving / Cutting Machine Discussion
    Replies: 4
    Last Post: 04-26-2007, 09:17 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •