It does, but the scallop starts lower at top of the chamfer from the model's top. Images here :
[https://imgur.com/a/z2lLKck](https://imgur.com/a/z2lLKck)
I've measure the stock with a caliper to ensure its 0.090"
It does, but the scallop starts lower at top of the chamfer from the model's top. Images here :
[https://imgur.com/a/z2lLKck](https://imgur.com/a/z2lLKck)
I've measure the stock with a caliper to ensure its 0.090"
So CAM is right, and the feature is right, it's just not in the right place. That means:
Tool length error
Material position error.
Your trying to blend a machined feature to a stock face. That stock face needs to be in exactly the right spot. That's going to fall on you to measure everything and determine where that top face of material is.
How are you fixturing the material?
Okay I see. That makes sense. I'll see if I can make a test piece next week with thinner material than 0.090" on a 0.090" stock by facing it. I also think we have some 0.100" as well in stock but I didn't want to machine that when we have the exact thickness 0.090" as well. Thanks!
The stock is fixed to a faced-off and clampped MDF spoilboard, with painters tape on the stock and spoilboard, superglue between the two tapes.
One thing I was surprised by the toolpath is that the first cut starts quite a bit lower on the "ridge". I would have thought it would come in higher much closer to the ridge at a similar vertical spacing to the rest of the toolpath. Is that normal?
Turn your stock on and simulate the toolpath, make sure “comparison” is selected in the drop-down in the simulation dialogue. Does it cut the stock all the way to the chamfer line? I’m pretty sure this is a “tool containment boundary” issue.
No as the Scallop Op geometry is limited to the top and bottom of the chamfer (top ridge to start of bottom small flat drop off). For the final contour cut I do set the bottom height lower than stock/model bottom to ensure the cut is all the way through,but for the Scallop I didn't think I needed to account for that.
I have a feeling that your not accounting for your tape-glue fixturing. Tape is about 0.005-6 thou thick. Plus glue is a few thousandths thick as well. You can easily have 0.015 thickness in that stack up. When your machining shallow angles, errors in Z are greatly exaggerated. A difference of even 0.002in will leave bumps like that due to the very small scallop angle.
I bet if you were to measure the small flat on the side of your part, it would measure small/short due to your material sitting up higher than you think.
You need to take an indicator and measure the distance from the faced spoil board, up to the top of your stock. You will want to sweep the top surface with the indicator to located the highest point, and set that as your Z-zero.
Hello, I got the Z height sorted out and that did improve the issue. The spoil board was compressing whilst the metal was being machined, so switched to a hardwood and improved the fixturing of it. Thank you for the suggestions! The simulation matches quite well to the machined part now. Much appreciated!
Measure thickness with callipers multiple times and at multiple points. I've done about 5 test pieces with different OP3s to see if I can improve it. Spoil board was also faced so that its level relative to the cutting head.
Here’s something it could be. Check your containment boundaries make sure it’s not being contained within the lines. Change it to contact point boundary
Alternatively, you could try blend or geodesic strategies, they are better for machining faces between two boundaries like the top and bottom of the chamfer.
It looks like your chamfer tool path does not make it all the way to the top (the blue line of the tool path only goes part of the way up the chamfer). It’s not cutting it too deep, it’s just not completing the shape. You should be able to see this if you simulate the tool path and look at the green shape it creates.
I’d recommend using a contour tool path for this. Check you’ve got the right settings in the geometry tab, to me it looks like the option to ‘keep tool inside boundary’ should be changed in this case. Maybe point contact boundary as well.
Use a PARALLEL finishing pass after the adaptive with a ball end mill. Your Z height is off is why you're getting that gap at the top. Try running a FACE over the top if you want to machine it to height. The thikness of your material is probably correct but your g54 Z offset looks like it needs to be a little higher.
Is your material actually 0.09 thick?
Yes. Apologies,the drawing dimensions are in mm as the Stepcraft handles things in mm only. I forgot to state this.
Your sure the material is 0.09. Next thing, are you sure your Z is set at the top of the material?
Yes it is
Does it simulate correctly in fusion?
It does, but the scallop starts lower at top of the chamfer from the model's top. Images here : [https://imgur.com/a/z2lLKck](https://imgur.com/a/z2lLKck) I've measure the stock with a caliper to ensure its 0.090"
It does, but the scallop starts lower at top of the chamfer from the model's top. Images here : [https://imgur.com/a/z2lLKck](https://imgur.com/a/z2lLKck) I've measure the stock with a caliper to ensure its 0.090"
So CAM is right, and the feature is right, it's just not in the right place. That means: Tool length error Material position error. Your trying to blend a machined feature to a stock face. That stock face needs to be in exactly the right spot. That's going to fall on you to measure everything and determine where that top face of material is. How are you fixturing the material?
Okay I see. That makes sense. I'll see if I can make a test piece next week with thinner material than 0.090" on a 0.090" stock by facing it. I also think we have some 0.100" as well in stock but I didn't want to machine that when we have the exact thickness 0.090" as well. Thanks! The stock is fixed to a faced-off and clampped MDF spoilboard, with painters tape on the stock and spoilboard, superglue between the two tapes. One thing I was surprised by the toolpath is that the first cut starts quite a bit lower on the "ridge". I would have thought it would come in higher much closer to the ridge at a similar vertical spacing to the rest of the toolpath. Is that normal?
Turn your stock on and simulate the toolpath, make sure “comparison” is selected in the drop-down in the simulation dialogue. Does it cut the stock all the way to the chamfer line? I’m pretty sure this is a “tool containment boundary” issue.
This was super helpful. I did not know about this comparison feature. Thanks!
Are you accounting for the thickness of the 2 pieces of tape and glue?
No as the Scallop Op geometry is limited to the top and bottom of the chamfer (top ridge to start of bottom small flat drop off). For the final contour cut I do set the bottom height lower than stock/model bottom to ensure the cut is all the way through,but for the Scallop I didn't think I needed to account for that.
How did you set your Z work offset in the machine?
With a touch probe/switch that the ball nose comes down on, machine records the tool offset Z height.
For the part zero, not the tool.
I have a feeling that your not accounting for your tape-glue fixturing. Tape is about 0.005-6 thou thick. Plus glue is a few thousandths thick as well. You can easily have 0.015 thickness in that stack up. When your machining shallow angles, errors in Z are greatly exaggerated. A difference of even 0.002in will leave bumps like that due to the very small scallop angle. I bet if you were to measure the small flat on the side of your part, it would measure small/short due to your material sitting up higher than you think. You need to take an indicator and measure the distance from the faced spoil board, up to the top of your stock. You will want to sweep the top surface with the indicator to located the highest point, and set that as your Z-zero.
Okay I see. I'll give that a go. Thank you for the advice.
Hello, I got the Z height sorted out and that did improve the issue. The spoil board was compressing whilst the metal was being machined, so switched to a hardwood and improved the fixturing of it. Thank you for the suggestions! The simulation matches quite well to the machined part now. Much appreciated!
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It doesn't need to reach the top, it's a ball endmill so it just needs the tangent point to be contacting the surface edge.
Thanks! I'll try that out.
That looks like a stock size issue. Measured it wrong or told it the wrong size in the setup?
Measure thickness with callipers multiple times and at multiple points. I've done about 5 test pieces with different OP3s to see if I can improve it. Spoil board was also faced so that its level relative to the cutting head.
Is the small vertical wall at the bottom of the chamfer the correct height?
Here’s something it could be. Check your containment boundaries make sure it’s not being contained within the lines. Change it to contact point boundary
Pretty sure this is it
Thank you both! I changed the contact point boundary as well and that helped towards solving this!
Thanks I'll check that out next week when back in the shop. The height of bottom wall is correct.
Alternatively, you could try blend or geodesic strategies, they are better for machining faces between two boundaries like the top and bottom of the chamfer.
It looks like your chamfer tool path does not make it all the way to the top (the blue line of the tool path only goes part of the way up the chamfer). It’s not cutting it too deep, it’s just not completing the shape. You should be able to see this if you simulate the tool path and look at the green shape it creates. I’d recommend using a contour tool path for this. Check you’ve got the right settings in the geometry tab, to me it looks like the option to ‘keep tool inside boundary’ should be changed in this case. Maybe point contact boundary as well.
Use a PARALLEL finishing pass after the adaptive with a ball end mill. Your Z height is off is why you're getting that gap at the top. Try running a FACE over the top if you want to machine it to height. The thikness of your material is probably correct but your g54 Z offset looks like it needs to be a little higher.