July 20, 2018 at 4:57 am #64230
Yea, pixels, or picas, whatever weird measurement system graphic designers use. I believe it also changed in the last version or two, which confuses people even more as not all the how-to’s have been updated to the new conversion factor.July 20, 2018 at 5:00 am #64232
I have tried setting it up in inches and mm, and also pixel. I have been following a tutorial on YouTube for converting the PDF to a cut. But of course, the tutorial is older and I wonder what has changed in newer revisions of the software.
The foam is 20×30 inches, and since I’m not starting in the corner of the machine, it’s going about 3-4 inches past the foam and crashing the gantry. I forgot to grab the laptop today to mess with it here at work.
I appreciate you helping me out since this is software related and not hardware. I was hoping someone here may have tried this with a dragknife. The machine seems to be working fine, with the exception of some vibration in the lines when drawing not parallel to an axis. I will work on that and post a pic if I can’t get it figured out. I’m guessing I still don’t have the belts tight enough.
JamesJuly 20, 2018 at 5:04 am #64233
The belts will wobble when cutting, if it’s not skipping, don’t worry about it. Too tight causes issues as well. Also as for inkscape, it might be importing too big too. Look through here if you haven’t already seen it.July 20, 2018 at 6:53 am #64252
I doubt I can add anything regarding the scaling issues between apps you’ve seen… you’re getting good help there, I think. I saw scaling issues, especially with the intro of Inkscape v0.92, but most seem to have gone away with a clean install of v0.92.3 on my LinuxMint box.
Since you’ve specified wanting to work with FT plans and have familiarity with the needle cutter, I’m assuming you’ve spent time on the FT forum. Jason Hitesman (jhitesma) has done several videos detailing PDF preparation for needle cutting using Inkscape and Estlcam… are these the ones you’re following?
Also, in post 1447 of my needle cutter thread, Shurakair describes PDF preparation of FT plans using Inkscape… he provides a foamboard template and describes moving the color-coded linework to different layers to control cut order and depth for different cut types using the Gcodetools. Check it out…
I don’t know of anyone who is actually cutting planes with a drag-knife on a regular basis… though several of us have certainly entertained the idea. One of biggest drawbacks is the need for corner compensation to avoid mangling sharp corners when cutting material as thick as foamboard (simple illustration is to stab butter with tip of knife and twist…). Donek Tools makes drag knives that can do the job and have also provided videos that demo not only cutting foamboard (note the lift actions on corners) but also explain the need for, and use of, their Excel-based “post-processor” to add the appropriate corner actions…
You might also find some useful info in the tangential knife thread in this forum.
I certainly recognize the problems with running a needle cutter on the family’s kitchen table but, apart from the noise, it is probably the quickest and most inexpensive way to get relatively clean and accurate cuts in foamboard.
— DavidJuly 29, 2018 at 4:45 pm #65025
Hey guys. Thank you so much for the help. Unfortunately I haven’t had time to try any of the linked techniques since the last time I was on here, but I have been doing tons of reading and watching all of the videos. While I haven’t seen anything I was doing wrong in particular, I have a list of things to try.
I am going to try to change the power regulator at work this week so I can give it a shot with the sd card at some point.
The only question I have this go around is this: Is there an online source for .dwg or .dxf files? I figured if I download something known to work, maybe I can work backwards and figure out where I’m going wrong. I am hoping there’s something like a Thingiverse for routers perhaps.
Thanks again to everyone for the great help. I hope to get back on this project this week and make some progress.
JamesJuly 31, 2018 at 6:10 pm #65236
Well I had some free time due to the rain tonight. I finished soldering some extensions for the steppers together and replaced the voltage regulator (Thanks Ryan!). I also tied the wiring harness together and ran it to a corner of the machine. It is so much easier working on it without the wires draped all over and getting in the way. It’s also much easier to be able to use the SD card on the display instead of having to plug into it every time with the laptop.
Anyway. I decided to start simple and got some Ford Mustang sketched off of Google and practice the rendering. I have figured out Estlcam and have a 1″ grid set up to verify the size of the finished drawings and they are coming out to fit on a standard letter sized paper. Unfortunately, it is still coming out almost double what it should be. Maybe 1/3 larger than the paper.
I uploaded a cnc file of the Mustang Fastback I’m working with in case any one is willing to look at the file and see if it’s Estlcam or Repetier blowing it up. I cannot find any information on this problem. I even counted the teeth on my pulleys to make sure I didn’t order the wrong ones by mistake. Everything is leaning towards it being a setting issue I can’t seem to figure out.
Again, I appreciate any advice on this.
Attachments:July 31, 2018 at 6:14 pm #65238
Maybe someone has a know functional cnc file of a ruler or something I could draw on a piece of paper they could post, that would be very helpful as well. I could then measure it and see if it’s pre or post Repetier.
JamesAugust 1, 2018 at 2:46 pm #65329
Ryan’s crown file is a known good set of gcode. Don’t forget to manually test distances by stepping in Repetier-Host some fixed amount, then measuring the distance traveled. If you ask for 100mm of movement and it moves 200mm it’ll mean one thing, if it moves 103mm it’ll mean something else entirely. 🙂August 1, 2018 at 4:38 pm #65339
Oops. That didn’t even dawn on me… Will do that. Thanks
JamesAugust 1, 2018 at 4:53 pm #65340
Ok. That shows something. With the ink pen mounted and touching paper, a 10mm jog comes out at 20mm. The 20mm jog is 40mm.
Could someone please tell me how to drop the settings in half please?
Would this be because I have some off brand drivers?
Thanks to everyone so far. I’m pretty excited to see if this fixes it.
JamesAugust 2, 2018 at 7:25 am #65358
Steps per mm, in Configuration.h of the firmware need to be cut in half.August 2, 2018 at 8:07 am #65366
Perfect. I’ll try it as soon as I get home.
JamesAugust 2, 2018 at 11:05 am #65387
And likely yes, you have A4988 drivers instead of DRV8825. The former will only do up to 1/16th stepping and the latter support 1/32.August 2, 2018 at 11:30 am #65392
That’s what I was hoping it was. I just wanted to be sure it wasn’t an error on my part. I’m doubting I would notice a difference in resolution with that small of a difference, but if I ever needed to, I will get the correct drivers. Those are what started my little fiasco in the first place.
JamesAugust 9, 2018 at 2:20 pm #65920
I just wanted to thank everyone for the help. Cutting the steps per minute in half seems to have fixed everything. It was pretty exciting seeing it draw in the correct scale right on to the foam board.
The more I read up on drag knives the more I think tangential is the way to go. Once someone has an easy plug and play firmware, I’ll give it a shot.
I ordered a 1/32 end mill and need to pick up a router and print the mount and give routing the foam a try next. It would be cool to get some planes cut out and glued up for when the wind stops around here and see how they do.
The end goal was to rout the parts for the Low Rider out of aluminum to build a cnc plasma cutter, so I’ll work my way up to that starting with some wooden stuff until I get some confidence.
Anyway, thanks again to all. I’ll post a pic of the plans it drew out from my phone.
JamesAugust 9, 2018 at 2:24 pm #65921
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