Lithophanes with uneven bottom border
Lithophanes with uneven bottom border
Hi everyone. We have been experimenting with lithophanes recently and they are working really well except at the bottom right the picture (where the cnc starts). Even though the photo has an level bottom. It slopes up by 4mm or so in the right corner. We are using 5mm acrylic and carving max depth of 4mm with a. 5mm radius cutter.
-
- Vectric Craftsman
- Posts: 118
- Joined: Mon Sep 19, 2011 12:02 am
- Model of CNC Machine: DIY 80/20 ~18"x48", Mach 3
- Location: Moore, OK, USA
Re: Lithophanes with uneven bottom border
A photo or few would probably help.
-
- Vectric Wizard
- Posts: 771
- Joined: Sat Jan 09, 2010 7:28 am
- Model of CNC Machine: cnc mako shark ext bed with HD 5 gantry
- Location: Buffalo,NY
Re: Lithophanes with uneven bottom border
Always post a photo of the problem your having, makes it a lot easier to help the person out.
Tony
Tony
What will matter is not what you bought but what you built; not what you got, but what you gave
Re: Lithophanes with uneven bottom border
Very good point. Here is the picture with the problem in the bottom right corner. You can see the slope.
- Xxray
- Vectric Wizard
- Posts: 2300
- Joined: Thu Feb 17, 2011 8:47 am
- Model of CNC Machine: CAMaster Stinger 1
- Location: MI USA
Re: Lithophanes with uneven bottom border
What do you use for hold down ?
Might be a case of deflection on the 1st line, when stress on bit & material is the greatest.
Might be a case of deflection on the 1st line, when stress on bit & material is the greatest.
Doug
Re: Lithophanes with uneven bottom border
We use some very strong clamps. There is no chance of movement. What exactly do you mean by deflection. If it was happening on the first line would it not show the error in the corner. Thanks for your help Xxray.
- Xxray
- Vectric Wizard
- Posts: 2300
- Joined: Thu Feb 17, 2011 8:47 am
- Model of CNC Machine: CAMaster Stinger 1
- Location: MI USA
Re: Lithophanes with uneven bottom border
Are you talking about the slight unevenness of the bottom cut compared to the bottom edge ?
A bit strains its hardest on the 1st pass, as the tip is 100% cutting through the material - On all other passes, it is only cutting through part of the material and doesn't strain as hard. It is a battle between the material vs bit, spindle/router and machine [and also whatever hold down method you use], sometimes the material wins and when this happens, the bit can deflect or snap, the machine itself can lose steps, or the material will come out of position.
Not saying that is the case here, I'm not sure I'm grasping what the problem is.
A bit strains its hardest on the 1st pass, as the tip is 100% cutting through the material - On all other passes, it is only cutting through part of the material and doesn't strain as hard. It is a battle between the material vs bit, spindle/router and machine [and also whatever hold down method you use], sometimes the material wins and when this happens, the bit can deflect or snap, the machine itself can lose steps, or the material will come out of position.
Not saying that is the case here, I'm not sure I'm grasping what the problem is.
Doug
- Mike-S
- Vectric Wizard
- Posts: 1123
- Joined: Mon Jun 13, 2011 6:45 am
- Model of CNC Machine: Joe's Hybrid 4x4 (but 3x3)
- Location: Hayesville, NC
Re: Lithophanes with uneven bottom border
I've found it helpful to put a boarder vector around the picture and cut it first at 1/2 the material depth. That can be done with a profile "ON" the vector and can be made with a couple passes. Then run the litho file (with the same tool) and the bit has far less material to cut on the first pass. Also the boarder adds a little class to the litho.A bit strains its hardest on the 1st pass, as the tip is 100% cutting through the material
-
- Vectric Craftsman
- Posts: 208
- Joined: Sun Jan 26, 2014 12:59 pm
- Model of CNC Machine: CAMMaster Stinger II
- Location: Romney, WV
Re: Lithophanes with uneven bottom border
What rastor angle are you using for cutting this litho? I usually use 315 which starts at the lower left hand edge and then cuts across diagonally. You only have the bit fully cutting in to the material on the first few, very short cuts that way.
With a small stepover value, that should minimize any deflection in the bit. I'm also assuming that you don't see this error on the preview within photocarve? It might be the angle of the photo but it looks like the bottom line of the litho carving is a bit higher on the left side, comes down in the middle and then slopes up on the right as you mention. Is it possible that the actual bottom of the photo you used to generate the picture isn't actually square along that edge?
May be way off track but just a couple of thoughts after looking at the photo you added.
With a small stepover value, that should minimize any deflection in the bit. I'm also assuming that you don't see this error on the preview within photocarve? It might be the angle of the photo but it looks like the bottom line of the litho carving is a bit higher on the left side, comes down in the middle and then slopes up on the right as you mention. Is it possible that the actual bottom of the photo you used to generate the picture isn't actually square along that edge?
May be way off track but just a couple of thoughts after looking at the photo you added.
- dhellew2
- Vectric Wizard
- Posts: 1322
- Joined: Thu May 22, 2008 10:14 pm
- Model of CNC Machine: Legacy Artisan 72 and AVID CNC Rotary
- Location: Royal City Washington
Re: Lithophanes with uneven bottom border
I always use a 315° angle which makes the first cut a hole. No strain on the bit, every cut is a step-over cut. My cut are usually with a 3/64" bit up to 0.20" deep single pass and haven't broken a bit yet while cutting.
Its difficult to evaluate without seeing the cnc in action, but, we can all make educated guesses
Did you create a border vector for your lithophane or just using the photo?
I always use a border, often not a rectangle, stars, hearts, etc.; just select the border vector then create the finish toolpath [and roughing if you use one].
Good Luck! Dale
Its difficult to evaluate without seeing the cnc in action, but, we can all make educated guesses
Did you create a border vector for your lithophane or just using the photo?
I always use a border, often not a rectangle, stars, hearts, etc.; just select the border vector then create the finish toolpath [and roughing if you use one].
Good Luck! Dale
You will get old if you live long enough!
Young = time, no money
Old = money, no time
Dale
Young = time, no money
Old = money, no time
Dale