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Depends on the rigidity of your setup. Have a vacuum table holding the stock and leaving a .015-.020 "skin" on said table so as not to break vacuum? Near-mirror finish. Granted, that assumes a willingness to do roughing passes on anything thicker than 1.25x the diameter of the tool and a .010" spring pass at full depth. A lot depends on the limitations of your machine, too. At work we can push 17kRPM and 400 inch per minute feedrates on all tools 1/2" diameter and up, so things don't take long to run even with roughing/finishing passes.
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Aug 13, 2021 23:59
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BattleMaster posted:I was hoping to machine some small PTFE (Teflon) parts with my 3018. Certainly even something as anemic as thins thing can handle plastic, right? I have a 3D CAD models of the parts (done in Siemens NX 12) I want to machine and I want to cut them from PTFE sheet. I read through all the comments and want to circle back around to here. Plastic needs stupid-high feed rates to cut well. The fast spindle speed actually hurts you on a 3018, because the leadscrews can't drive fast enough. Set your spindle to max RPM and your feeds to as fast as the machine can go, physically. Like, max unloaded travel rate-10%. I got decent-enough results on my 3018 that way in UHMW, which machines a little better than PTFE (in my experience). I wasn't using a $50 bit, but I did get some ones that were better than the 5-for-$10 ones. The ones with the 7/32" cutting diameter and 1/8" shank worked the best. I can't find them on Amazon right now, sorry.
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Aug 14, 2021 04:28
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Looks like the ShopBot post processor for CAMworks I hired someone for is pretty good. I haven't tried drilling ops and other canned stuff yet, but if anyone wants to give it a whirl hmu
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Aug 19, 2021 22:49
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Reporting back, I'm getting wonderful results in polycarbonate (lexan) on my 3018 using some cheap HQMaster 2mm single flute edge mills @ 9000rpm (that's all the stock 3018 does) and 500mm/min feed rate. Just doing pocket cutouts on flat sheets. I'm using bCNC on a raspberry pi 3 to send to grbl on the controller. I just need to figure out better software for laying out panels. I can't really do the PCB software into FlatCAM as it doesn't understand non-circular cutouts very well. And carbide create is a real piece of crap and makes weird paths. I guess I'll check out using inkscape or other 2D vector drawing into pyCAM next? Unless there's any other suggestions. Basically just trying to do pocket cutouts and occasional lettering engraving on flat sheets, like you might otherwise order from https://www.frontpanelexpress.com/ using their software. Rescue Toaster fucked around with this message at 16:15 on Aug 22, 2021 |
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Aug 22, 2021 16:09
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Rescue Toaster posted:Reporting back, I'm getting wonderful results in polycarbonate (lexan) on my 3018 using some cheap HQMaster 2mm single flute edge mills @ 9000rpm (that's all the stock 3018 does) and 500mm/min feed rate. Just doing pocket cutouts on flat sheets. I'm using bCNC on a raspberry pi 3 to send to grbl on the controller. The Inkscape-to-Gcode plugins were not all terrible as long as you didn't care that they only ever went 100% spindle at 100% feed. In your case, that sounds like the desired behavior. Setting up all the weird inkscape layers to get the inkscape space to translate 1:1 with the machine space was involved solvable.
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Aug 22, 2021 20:14
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If you're doing 2d cutouts Carbide Create is easy to use and does the basics without much trouble. Ive been using it for simple signs and things like that. Spits out GRBL. Edit: Saw you tried it already, whats weird about the paths? Haven't seen anything too strange myself.
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Aug 22, 2021 20:38
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Sedgr posted:If you're doing 2d cutouts Carbide Create is easy to use and does the basics without much trouble. Ive been using it for simple signs and things like that. Spits out GRBL. Just really clunky interface to start with. For example you can't click on an object and set the position manually by typing it in, you can only set the size. I keep getting weird paths when trying to select overlapping objects, like if I need to create a rectangle with rounded bump-outs in a couple spots. When you select them and create the path it'll sometimes choose randomly to treat some objects as negatives/cutouts and then I'll re-click them and recreate and it'll choose a different random pattern of unions/differences. Took like 6 tries last time to get the correct path. If you just drag and select all the objects and then create a path you get a random different partial path every single time. EDIT: Oh and if you're milling down by like 0.3mm in layers, it'll lift the tool to the safety height between each pass for no reason. Rescue Toaster fucked around with this message at 22:26 on Aug 22, 2021 |
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Aug 22, 2021 22:11
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Could try one of the Vectric packages they might be better suited. They cost money but are well regarded. Free trials with limitations so might be worth a try just to look at the software. Cut2D or vcarve maybe.
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Aug 22, 2021 22:56
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Kiri:Moto might be worth checking out? Looks like there's some pretty comprehensive guides, and it's just CAM in the browser. I haven't used it myself in any real way, just kinda tooled around once or twice.
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Aug 22, 2021 23:58
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Has anyone on the hobby side personally tried a 3D printer firmware for cutting? Klipper and Marlin can both disable the need for temperatures and drag a cutting head around just fine, as well as benefiting from all the 'features' of those firmwares (good acceleration control comes to mind) and driving software like OctoPrint. I looked at it briefly and for some reason the gcode dialect has drifted apart, so I don't know if there's a drop-in way to do it.
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Aug 23, 2021 15:14
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I see no reason to re-invent the wheel as far as that goes? Also that's literally what Kiri:Moto does that NewFatMike mentioned above (at least, search results for it has text describing it as a browser-based slicer for printing, laser cutting and CNC milling)? https://grid.space/kiri/ I'd be very careful about just taking code generated by this slicer and running with it, though. Read all of the documentation/etc. EDIT: Or just watch this video to see if it's something you want to play with. https://www.youtube.com/watch?v=08795Sj22QE Some Pinko Commie fucked around with this message at 16:09 on Aug 23, 2021 |
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Aug 23, 2021 16:04
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I was more talking about the controller hardware / firmware stack, to be followed up later on with a question about why the common toolchains don't generate my snowflake gcode.
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Aug 23, 2021 21:07
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My previous table for the Onefinity was not cutting it. Enter table version 2. Closed.  Open.  Activate disco mode. https://i.imgur.com/WzDXQvJ.mp4 Few things to finish up. Wiring isnt final, got some extensions on the way. The quick change table I ordered isnt due to arrive for a bit so there will be a slight change to version 3 but it'll do for now.
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Aug 24, 2021 22:08
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Just pulled the trigger on parts for a lowrider cnc. I'm mainly planning to use it for roughing out templates in 1/4" mdf and maybe some sign making. Only thing I still have to acquire are the stainless rails.
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Aug 31, 2021 01:00
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This is kind of a long shot, but the laser thread seems to be locked and I'm not aware of a new one, so I'll try here: Anyone in the Des Moines area got a laser they'd be willing to do some wood burning with for me? Money's on the table. Only gotcha is that it's a late addition to the project and while there's no hard end date, I don't want to stall completion so I'd be hoping to get it done within a week.  If there's a better place to ask, I'm happy to take this there.
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Sep 2, 2021 03:12
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Are there any maker spaces in the Des Moines area? I'm sure someone there would be happy to.
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Sep 2, 2021 03:20
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Good point, I forgot about them, cheers.
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Sep 2, 2021 03:50
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Any ideas for lining up additional cuts on the same piece, or more specifically, an existing work piece I want to add some drills to? It seems like there should be something like a ring XY probe that you could automatically probe to set the XY=0 point to an existing drill hole/mark, but I've not seen one available. The best plan I could come up with would be to mill holes in the spoil board that I can use to line up the work piece (since in this case it has some holes, so I could basically screw it down to the spoil board with that). Then it's not too different than any other tool change: do the holes, mount the work piece, probe the Z without changing XY, tool change, cut... This wouldn't necessarily always work depending on what you're doing, and accuracy could vary depending on the type of screws and the spoilboard material, so I'm curious of other ideas. I'm also curious if anyone has ever tried to panelize a design (cut mutiples of the same design in a grid). Seems like you'd have to do it entirely at the CAM step or generate separate gcode for each tool, assuming a gcode utility exists for panelizing.
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Sep 2, 2021 23:08
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Rescue Toaster posted:Any ideas for lining up additional cuts on the same piece, or more specifically, an existing work piece I want to add some drills to? It seems like there should be something like a ring XY probe that you could automatically probe to set the XY=0 point to an existing drill hole/mark, but I've not seen one available. This is a great use case for locating features. Frequently, through holes are used because you can triangulate very easily on a cylindrical face. Alternatively, you can use machined edges as references. It is substantially easier if you haven't moved the part. quote:The best plan I could come up with would be to mill holes in the spoil board that I can use to line up the work piece (since in this case it has some holes, so I could basically screw it down to the spoil board with that). Then it's not too different than any other tool change: do the holes, mount the work piece, probe the Z without changing XY, tool change, cut... This wouldn't necessarily always work depending on what you're doing, and accuracy could vary depending on the type of screws and the spoilboard material, so I'm curious of other ideas. This is fundamentally a fixture plate. Dowel pins or gauge pins (depending on your level of precision) are great locating uses. Check out a few posts to get some juices flowing: https://www.cnccookbook.com/complete-guide-to-fixture-plates-tooling-plates-and-modular-fixtures/ https://blog.tormach.com/fixture-plates quote:I'm also curious if anyone has ever tried to panelize a design (cut mutiples of the same design in a grid). Seems like you'd have to do it entirely at the CAM step or generate separate gcode for each tool, assuming a gcode utility exists for panelizing. Sounds like you're talking about nesting or palletizing: https://www.youtube.com/watch?v=orh-DzwONb0 E: fixturing and jigs are loving fun. Way more fun to help folks at the makerspace with that than CAM
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Sep 2, 2021 23:17
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NewFatMike posted:This is a great use case for locating features. Frequently, through holes are used because you can triangulate very easily on a cylindrical face. Alternatively, you can use machined edges as references. It is substantially easier if you haven't moved the part. You hit the nail on the head. Particularly with the "mitee bites" shown in the first link. I can't tell you how many one offs I made where a vice would've ben in the way so I made a consumable "clamping bar" that went between my mitee bites and workpiece.
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Sep 3, 2021 00:36
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I love mitee bites. I've been walking a set of vise jaws around the shop getting other people to try them like some kind of missionary. As for the multiple parts you're looking at work offsets. G54/G55/G56 etc. Each one let's you define a new zero. You can program multi part as a huge assembly but if you use work offsets you only have to program one part's toolpath and if you make a new fixture or only want to run a part you can.
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Sep 3, 2021 02:04
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Bad Munki posted:Good point, I forgot about them, cheers. you can also try local crafts stores. the fabric store by me has one. Also I think the public library has one? anyway, try those too i guess idk
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Sep 3, 2021 06:01
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The Shariff DMC 2 Desktop CNC is approaching Kickstarter. Inventor has been uploading videos over the last month. I bought a DMC1, but got busy with property investments and didn’t get around to really using it. It seems strong and rigid? https://youtu.be/PppsTAgAM3I Anyway, somewhat envious for those who will get version 2. In terms of desk top CNCs, the competition is a joke.
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Sep 7, 2021 04:15
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I mean, closed loop motors are nice, but I'm not seeing that much that really makes it stand out from every other machine on the market at the $3500-5500 price range on their kickstarter?
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Sep 7, 2021 11:54
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Any goons interested in (or work at a place that might be interested in) a metal machining project? I've got a double-sided CNC job that's bigger than I can fit on my machines, and that would be to be done out of like a really hard Corian material or a metal (aluminum would work). Piece would be around 12.25" x 12.25" x 1.75". Would need an NDA signed because it's for a big client. PM me or Edit: Removed my e-mail.
Harvey Baldman fucked around with this message at 20:06 on Jan 5, 2022 |
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Oct 26, 2021 02:56
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Oof, bigger than what I can fit, unfortunately.
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Oct 26, 2021 05:00
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Just finished making a fixture plate for my mill. It is in the same style as the Saunders Machine Works ones but they don't make one in the size I wanted. The plate is 10"x16"x1.5" Holes are drilled and tapped 1/2NC with a 0.25" deep 0.5005" counter bore. The counter bore allows alignment dowels to be used for repeating setups. Getting the bores right took quite a few tries in a test piece to get the boring head dialed in. 
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Oct 26, 2021 05:16
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Have you given thought to keeping chips out of all those nice holes?
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Oct 26, 2021 17:42
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Commodore_64 posted:Have you given thought to keeping chips out of all those nice holes? That's what peering directly into the holes while blasting them with shop air is for!
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Oct 26, 2021 17:51
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Commodore_64 posted:Have you given thought to keeping chips out of all those nice holes? We use o-rings and pennies to "plug" unused holes on similar fixtures at work (except those fixtures double as vacuum plates, so the vacuum helps keep the holes from getting shavings in them by pulling the pennies against the o-rings). Then you can do this: insta posted:That's what peering directly into the holes while blasting them with shop air is for! While wearing safety glasses (and keeping your mouth shut) and not worry about blowing shavings deeper into the fixture.
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Oct 26, 2021 18:34
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insta posted:That's what peeing directly into the holes while blasting them with shop air is for! Lol. Also, I was daydreaming of some little 3d printed plugs with a slot to lever them out of. Maybe add some of those O rings and go to town! I love the idea and will totally steal (re-steal?) it one day.
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Oct 26, 2021 18:53
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Who among us hasn’t stepped back from the machine with an air gun in hand and chips in hair?
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Oct 26, 2021 19:17
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Are you even a machinist if you haven't?
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Oct 26, 2021 21:06
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Someone once told me the definition of a good machinist is one that still has all of their digits after 5 years full-time working with machinery. I don't quite think that still holds true any more because I still have all of mine and I'm still learning things, and I've been working with "manual" powered and CNC machinery since 1998 (though to be fair most of that machinery was built prior to that, the most modern machine in the shop where I work now was built in 2005).
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Oct 26, 2021 21:09
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insta posted:That's what peering directly into the holes while blasting them with shop air is for! Hey, no peeking in my shop! They do make a wonderful screeching whistle when you blow shop air over them though. I was thinking of making an injection mold to make plugs but then I found that saunders machine works has plugs available so I am ordering them from there. Right now, I am just taking the plate off and dumping it out after a job is done.
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Oct 26, 2021 21:14
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Honestly the best part about machining is that there's always new things to learn and new ways to skin the cats, that's why I think the chips in the hair is the best definition  Nobody likes working with the machinist who acts like they've learned and know everything.
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Oct 26, 2021 21:14
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If you're using your milling machines to skin cats you're doing it wrong. That's what lathes are for.
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Oct 26, 2021 21:19
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Psh, like nobody has put a piece of stock in their mill spindle and a cutting tool in their vise before
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Oct 26, 2021 21:30
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At work the other day i was washing my hands and saw a glint in the mirror and assumed I had aluminum in my hair again--"industrial strength glitter," I like to call it. Nope, it was a just an unexpected silvery gray hair!
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Oct 26, 2021 23:46
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Brass makes my favorite shop glitter.
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Oct 27, 2021 00:23
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