STL import problems

[Z-clip]

Howdy folks:

I’m having some difficulties with a pattern.

My original STL was created .6875 (11/16) “ thick. My desire was for the CW to start at the surface but it is insetting the pattern into my test board, making the bottom of the deepest cuts very close to the piercing threshold, to the point where I am getting small voids thru the board. In my CW Soft, my depth is set for .75 (Thickness of test board) should I have that set for depth of pattern instead? Should I be setting the surface plane at .75” up from origin in my modeling soft before exporting to STL?

The other difficulty is having the machine not cut the top edge. My final product boards are very close to finished width, and I’m not comfortable with how close the carving bit gets to the Board Tracking Sensor when I cut the top edge of the pattern. I used the pattern editor to erase that section of the pattern, but the machine still cuts a small ammount around the upper corners such that when I remove the finished piece from the board, and undercut my end pieces, I still have some carving marks on the face of the piece near the top. At this point, I can only think to add extra width to the ends of the STL and re-import, cutting final width one the mitersaw, which is kind of a pain because my patterns are being imported out of scale for some irritating reason, and I have to resize them by eyeball.

If i've done this correct, there should be a refrence image below.

48392

As always, any help is greatly appreciated. Thanks for your time.

-Z-

[James RS]

Can you post it?

[mtylerfl]

Hello,

When you exported the STL as a PTN, you may have had the box checked for the Zero-Z Plane to be placed (referenced) at the bottom. If so, then when you bring into Designer the "Pierced Carve" box will automatically be selected. Uncheck that and the pattern should be placed back to referencing the Z axis from the top of the board.

EDIT: The Carve To Full Depth is what I meant to say...it's not a "checkbox"...rather, it is a button. See the pic below...

[Digitalwoodshop]

I have done Ovals and all the Big Accountability Board handles and the machine has never cut the brass roller... IT always steps over it.... Leaving a wider Tab at the bottom. And since Cut Paths are always on the front or second side to carve for a 2 sided carve, there is no problem cutting away the brass roller wood....

I don't have STL so I am not sure if the same rules apply...

The picture showing the front and back board shows it best.... Look at the tape area...

AL

[mtylerfl]

...
I don't have STL so I am not sure if the same rules apply...

The picture showing the front and back board shows it best.... Look at the tape area...

AL

Hi Al,

Same rules apply, regardless. An STL cannot be used directly in a Designer layout...it's always going to be a PTN when used in an MPC layout. (The CarveWright STL Importer converts the STL to a PTN so it can be used in the Designer software.) A Cut Path much less than 1/2" from the top of the board will leave a bigger/shallower "tab" automatically over the Brass Roller area, as you stated and kindly showed in the photos. Thanks for the pics!

[jpaluck]

Z

I had the same issue with a small amout the depth of a hair being carved off the the top. LG helped me with a work around while back..try adding a carve region over the area you dont want cut and set it to zero..fixed my issue..hope it helps

[mtylerfl]

Z

I had the same issue with a small amout the depth of a hair being carved off the the top. LG helped me with a work around while back..try adding a carve region over the area you dont want cut and set it to zero..fixed my issue..hope it helps

Hi John,

I think he meant the top edge of the board (as in carving deeply at the board edge over the Brass Tracking Roller area).

The problem of "shaving" the top SURFACE like you described is usually caused during bit homing when the bit touches down on the board surface...soft wood especially gives a slightly lower "Z" due to the bit very lightly "squishing" into the board surface...or, the board may have slight thickness irregularity at the point of "touchdown" so the "Z-zero" might be different at other areas of the board. We're talkin' just thousands of an inch normally, but enough to see it "shave" the top surface when you think it should be "zero" where the bit should ignore. The zero carve region trick works well for certain projects and have used it myself. More often than not, I just don't even worry about a little "shave" though!

[mtylerfl]

At this point, I can only think to add extra width to the ends of the STL and re-import, cutting final width one the mitersaw, which is kind of a pain because my patterns are being imported out of scale for some irritating reason, and I have to resize them by eyeball.


Forgot to tell you the probable reason your PTN's are coming in out of scale is that the Scale To Fit box is checked. Once you uncheck that box BEFORE placing the PTN on your board, your STL/PTN conversions should come in at the original intended scale. (I do it all the time...no problem with scaling as long as you uncheck that box - it is "ON" by default...I think it should be "OFF" by default because it's so often overlooked.)

[Z-clip]

Howdy folks:

First off, thanks to everyone for your responses. They were all very helpful for more than just this project.

The “Zero Depth Carve Region” trick did exactly what I wanted at the top of the pattern. I applied it (for obvious reasons) after placing the pattern. I am curious to know if a Carve Region function will always override a pattern, or if the operation is governed by the order of application. In any case this info will be extremely useful on future projects. I might even import my vector design as a “ZDCR” (Can I coin that acronym/initialism?) and overlay the surface of my project to alleviate that nigh deliberate certainty of the CW to carve out the top x hundredth of an inch of board surface. Which brings me to the next issue.

Though turning off the “Carve to Full Depth” button in the Pattern Editor soft helped a great deal to bring the carving closer to the top surface of my stock, it would seem that the assessment of “Bit homing into soft material” is spot on, and this little kernel of info has come just in time to save what little hair I have left from being completely pulled out at the root in my frustration. I can always take it down w/ a hand plane.

Lastly I am still uncertain if un-checking the “Scale to fit board” box had any effect. The one import that came in too small was still too small, but all the others came in at the proper scale. I created them all in the same “world space” in my 3D soft, so I’m uncertain why one would be out of scale and the others aren’t, but I may have done something when I broke them up into discrete files before exporting them off to STLs. I went ahead & exported additional copies as DXFs and double checked the dimensions with my vector soft, the DXF was the right scale, so I just re-exported a new STL for that piece, though I haven’t converted it to a pattern yet. I’m chalking that one up to PEBCAK (Problem Exists Between Chair And Keyboard).

This time I did my test cut with the new changes in one of the end pieces that mounts to the wall (+/- 30min carve time). Everything carving-wise went smoothly but I think I may need to find a different test material to work with other than MDF (I’m thinking new subject thread here). I’m having problems with the lid switches returning to a closed State and the Bit Plate has lost it’s “switchblade like action” and usually takes a couple of tries to extend all the way out to where the bit can touch it. I'm fairly confident this is because MDF creates such a fine dust when carved that it's gumming up the works even with periodic pause, vaccum, blow, continue sessions during the carving process.

Below is a pic of the end plate. I already cut the edge that attaches to the wall, but we can all see both the ZDCR result and that Bit Homing annoyance. Thanks again everyone.

-Z- "All's well that ends...period!" -unknown-
48485

*UPDATE*: Scaling problem occurs from improper STL import. On a couple of the STLs "Model Design Units" defaulted to cm instead of inches, where as "Working Model Size" was in inches, causing a reduced aspect ratio. I really don't remember changing that.