3D Equal Scallop Tool Transition Mark on Surface

[Omar_IME]

Hi everyone, 

Good day, i have one issue with transtion mark on 3D surface when using Equal Scallop. Please refer to the picture below. Tolerance is 10 micron. 

 

 

[JParis]

Looking at the general shape of that part, I'd look to using Flowline instead.

[JoshC]

I would raster that one, raster is a parallel cutting toolpath and we could run the tool up and down that face and it would output good G18/G19 arcs if filters are used properly, that is how i would do it is raster, going from left to right (so like 0 or 90 degrees, cant tell from the pic where X and Y directions are but likely 0 or 90 degrees) and this would give you good vertical G18/G19 arcs that will leave a great finish compared to linear code.

Or flowline like Jparis mentioned, i would do the same flow direction to make the tool go up and down that surface so you can get good arcs. 

[crazy^millman]

Like the others have said your using the wrong toolpath to achieve what your after. Use the correct toolpath that doesn't transition on the surface like that and you will be good. The problem is tool deflection and machine inaccuracies when you doing what your doing. This is more about knowing how to machine a part than what the software can do. Want to test what I am saying put a tool on a surface 1 micron above the surface. Then I want you to kick it up to 20K and watch how the surface is then machined. Then I want you to move the tool just 10 microns in a circle again while 1 micron away from the surface. If you could see all the physics and everything going on with that end mill as it flexes and moves and all the other things going on then you will understand why the toolpath itself was not at fault it was just a poor choice of toolpath to use in that situation. What looks good on the screen is just a picture there is so much more to making parts than what you see on the computer screen. Be a machinist as much as a programmer and these things will be less of a problem. 

I was in Johor Bahur some years ago doing work and really enjoyed my time while working in Malaysia.  Hopefully we see more questions to help you become a better programmer. Have a good day and a Merry Christmas. 

[AMCNitro]

5 hours ago, Omar_IME said:

Hi everyone, 

Good day, i have one issue with transtion mark on 3D surface when using Equal Scallop. Please refer to the picture below. Tolerance is 10 micron. 

 

 

Wrong toolpath.  It looks like you're making molds and that's where your cores go.  At my previous job the other programmer used scallop the same way you're doing it, and it WILL look like poop.  You can use flowline, or what's better in my experience, 2d swept.  

[AMCNitro]

4 hours ago, 5th Axis CGI said:

Like the others have said your using the wrong toolpath to achieve what your after. Use the correct toolpath that doesn't transition on the surface like that and you will be good. The problem is tool deflection and machine inaccuracies when you doing what your doing. This is more about knowing how to machine a part than what the software can do. Want to test what I am saying put a tool on a surface 1 micron above the surface. Then I want you to kick it up to 20K and watch how the surface is then machined. Then I want you to move the tool just 10 microns in a circle again while 1 micron away from the surface. If you could see all the physics and everything going on with that end mill as it flexes and moves and all the other things going on then you will understand why the toolpath itself was not at fault it was just a poor choice of toolpath to use in that situation. What looks good on the screen is just a picture there is so much more to making parts than what you see on the computer screen. Be a machinist as much as a programmer and these things will be less of a problem. 

I was in Johor Bahur some years ago doing work and really enjoyed my time while working in Malaysia.  Hopefully we see more questions to help you become a better programmer. Have a good day and a Merry Christmas. 

The problem I run into a lot these days is that you have programmers that were not machinist first,  so they don't understand all the stuff you're describing.  They never learn how tools actually cut and they don't see the tool deflection, amongst other things.

[Omar_IME]

Thanks everyone for helping. Gladly to hear some advice from everyone .5th axis CGI, oh really, welcome to our country. Drop me a message if you come here again. Im staying at Penang. But do we have any specific reason why this transition mark happen? I thought before to use flowline as the passes transition is at the end of surface. But anyway, do we have any specific reason of this issue happen? Is it because of tool deflection cause it to vibrate? If that so, if i clamp tool shorter it would eliminate this issue right? 

[Leon82]

You have Accel decel jerk backlash deflection and kinetic energy to fight when you use the scallop and change directions on the surface

[crazy^millman]

14 hours ago, Omar_IME said:

Thanks everyone for helping. Gladly to hear some advice from everyone .5th axis CGI, oh really, welcome to our country. Drop me a message if you come here again. Im staying at Penang. But do we have any specific reason why this transition mark happen? I thought before to use flowline as the passes transition is at the end of surface. But anyway, do we have any specific reason of this issue happen? Is it because of tool deflection cause it to vibrate? If that so, if i clamp tool shorter it would eliminate this issue right? 

No there is so much going here that for what your trying to machine and the finish your trying to obtain you would never want to transition any toolpath in that area of the part. You have a half moon shape why in the world would you want to introduce any transition to change in motion in the area you have shown us? UG and Mastercam picture means nothing. Show me both sets of code and both methods of programming then we can compare apple to apples. Really drives me crazy people comparing software when they don't understand basics physics, machine mass and inertia related to machining a part.

Lets take driving a car and use it as an basic example here. Your driving on a oval race track and you decided to start at the very most outside of the track and then move slightly in for our example .1 per lap. Let say the track were 500 feet wide. That would require 500 divided by .1 to give us 5000 laps. Now being 500 feet wide we know the size of the oval on the outside of the track was not the same as the inside. Now if we drove correctly and made the overlap move constant we should never slow down or change our inertia. Now that would be what I am seeing in the NX picture. Now in the Mastercam picture we have our race car not going in the same direction and constantly changing direction, but expect to see the same exact results from both races and uses of the race car.

Now what we are suggesting is to program the machine in such a way we are running our motion in smooth and constant method and ways. Controlling the movement and process to not allow constant changes in direction is what using one of the other toolpaths we have mentioned would do or change it be in the place of the part where it would not matter. 10 microns for those playing along at home is  0.00039 tolerance. Now we don't know if that is bilateral or unilateral, but that is extremely tight tolerance to hold with any milling application. 

If I am ever back on that side of the world I will give you a PM and maybe we can meet. Have a good night and hopefully my explanation made sense and gave you something to think about.

BTW my name it Ron. 

[Omar_IME]

Sorry Ron. I would never compare any cam system as I already use few cam's systems except UG. But usually we as a reseller would face something similar if facing ex UG user and  i never use UG before to bring any conclusion for their question. Anyway, I already solved it last time by manipulating the Arc Filter and Tolerance. It solved for both faceting surface and tool mark. I just need some time to find the solution. I am using the lastest Mastercam and through Advance Toolpath View, we can see the dotted lines along the toolpath. So after compare Tranditional 3D Surface Finish and Scallop or Waterline which solve the mark and faceting surface issue. I can concluded that the solution for any toolpath that effect our surface finish is, the Scallop toolpath have way more points distributed along the toolpath while for 3D Surface Finish have lesser points. So all I need to do is to tighten the tolerance and set some of the parameters in Arc Filter and Tolerance.  it will gave the same surface quality o ou part. I tested on a simpler part to find the root cause of this issue.

Thanks for all advices everyone.