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i just set it for whatever and hope nothing breaks.
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Oct 29, 2013 03:53
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| # ? Apr 18, 2024 15:33 |
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so far lots of stuff has broken
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Oct 29, 2013 03:54
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whatever doesn't kill you
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Oct 29, 2013 04:38
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CarForumPoster posted:I shall explain it then. 1% of cutter diameter per tooth is a good rule-of-thumb starting feed rate for milling aluminum. for serious tho this is good advise, thanks
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Oct 29, 2013 05:26
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You are welcome.
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Oct 29, 2013 17:38
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Designing a CNC for making PCBs on no real budget with no real idea what I'm doing   Those bottom rails slot into a drill press table I can probably convert for a Z axis.
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Oct 31, 2013 21:59
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Substrate Mills are pretty crazy stuff.
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Oct 31, 2013 22:26
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ante posted:Designing a CNC for making PCBs on no real budget with no real idea what I'm doing Setting up parallel guide rails can be pretty tricky (at least for hobbyist 3d printers). It looks like you're just going to capture the rods in holes in the angles on each end, but getting four holes that allow for two perfectly parallel rods is easier said than done. Maybe you could include some adjustability there? my ideas are terrible: #1 capture the rod ends in small plates that can float in oversized holes with nuts and bolts. #2 what if you relied on something else to join the two square tubes and then split the angles on each end into thirds so that each pieces that could be adjusted/shimmed individually?
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Nov 1, 2013 01:37
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gently caress. I forgot one parameter in my CAM software that always gets me and now I have two 5-hour jobs that were cut improperly by 50 thousandths. Fffffffffff It's recoverable, but drat
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Nov 1, 2013 03:02
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kafkasgoldfish posted:Setting up parallel guide rails can be pretty tricky (at least for hobbyist 3d printers). It looks like you're just going to capture the rods in holes in the angles on each end, but getting four holes that allow for two perfectly parallel rods is easier said than done. Maybe you could include some adjustability there? I was going to maybe add a couple square tubes in the centre to join the square tubes/increase rigidity instead of just relying on the angles. You've got a good point with the holes in the angles. I was thinking of maybe using my drill press to go right through both sides of some square tube, then cut that into two angles. That will still result in mis-centred holes on opposite sides of the face, though. Hrm. Drilling long-ways through rectangular tube and then splitting it might work. I don't like that, though. What are my odds in being able to make a jig out of wood and keeping the holes pretty accurate? Splitting the pieces shouldn't be a problem. I can put another piece of angle behind them to keep the rods in, it'll be able to keep them square, too. I dunno. I'll think about it. Tomorrow I should have a revised version. Amateur machine accuracy is so difficult.
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Nov 1, 2013 03:14
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Sagebrush posted:gently caress. I forgot one parameter in my CAM software that always gets me and now I have two 5-hour jobs that were cut improperly by 50 thousandths. Fffffffffff this is why you should never do anything that matters
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Nov 1, 2013 04:06
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ante posted:I was going to maybe add a couple square tubes in the centre to join the square tubes/increase rigidity instead of just relying on the angles. One other thing, you can probably leave one end of the threaded rod hanging instead of seating it in the far plate. Depending on how much $$ you put into the rod and how well it's seated against the stepper, it may not be perfectly straight and one end might have some wobble (even a tiny amount could cause some binding). For the platform, are you going to use linear bearings? edit: You might consider using using aluminum extrusion from someone like Misumi. It would simplify the assembly significantly. kafkasgoldfish fucked around with this message at 02:10 on Nov 2, 2013 |
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Nov 2, 2013 01:59
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I'm planning on spending almost no money on this if I can help it. All of the linear motion stuff is salvaged from a bunch of free printers/scanners I got. Some 13" rods and brass bushings. I can carve out a pillow block for the bushings out of some 3/8" acrylic or something. Aluminum extrusion would save me some hole-drilling in the square members, at the cost of some stiffness. So I might do that for a prototype, I'd ideally like to throw this together as fast as possible. So I've got this, now:  I added some squares in the middle, and I'll just use some threaded rod through the whole assembly and torqued down really tight to keep everything stiff. The linear rods are held by holes in the inner angles, and kept from slipping out by a solid/undrilled outer angle. I'm really not sure about the rod straightness solution I had going in my head last night, though. I'll do some googling for good ways to make it pretty accurate, but maybe I'll have to do some loving around when it's all built. Oversize the holes, fill them with hot glue and slide the platform back and forth a whole bunch? I dunno. I'll work on the motor assembly and coupling next.
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Nov 2, 2013 05:28
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ante posted:I'm planning on spending almost no money on this if I can help it. This seems like it has a lot of extra parts, why not just make the table follow the square tubing and the lead screw pass through the cross members?
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Nov 2, 2013 06:40
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Seems to me that the linear rods are necessary for accuracy. I could lower the platform like you say, but then there's nothing stopping the side-to-side motion or the up-and-down. Square tubing isn't exactly built to tight tolerances, so bearings wouldn't go over the surfaces perfectly smoothly. Or am I overlooking something?
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Nov 2, 2013 19:38
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Unless you're ordering ground rods, which might be a good idea theyre not too much more expensive, theyre basically extruded in the same way. Dont expect your straightness per foot to be great with rod either. If you could get thick walled tubing (or just solid, this is the base of a machine) weld it all together and then just square it up on a bridgeport you'll find massive improvements in all these regards. Keep in mind weldings not going to leave anything square so unless you line bore the holes for the control rods after welding they'll be pretty far off as well. This is why eliminating them and machining a control surface is probably the best idea. Do you know anyone with a mill?
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Nov 3, 2013 17:38
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I've got a bunch of rods salvaged from printers and scanners and no access to a welder or mill. A mill would be pretty keen 
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Nov 3, 2013 20:34
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ante posted:I've got a bunch of rods salvaged from printers and scanners and no access to a welder or mill. Good news is if the rods have ends that are mounted together to make a continuous rail theyre likely pretty good tolerance wise. I.E. if its all one assembly, hooray.
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Nov 4, 2013 06:33
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CarForumPoster posted:Unless you're ordering ground rods, which might be a good idea theyre not too much more expensive, theyre basically extruded in the same way. Dont expect your straightness per foot to be great with rod either. If you could get thick walled tubing (or just solid, this is the base of a machine) weld it all together and then just square it up on a bridgeport you'll find massive improvements in all these regards. This is just a pcb mill, seems like solid tubing, milling and welding are a bit over the top. He could build the frame out of dimensional oak 2x2s and cheesy galvanized brackets from THD it'd be more than rigid enough. Also, what is the scale of this thing? If you're using scrap components from printers and the like, none of those rods can be much more than say 12-16"? p.s. misumi extrusions are like $1/10cm, are totally sufficient strength wise and they'll cut them to length for free. last time I'll mention it.
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Nov 4, 2013 17:38
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My concerns weren't of rigidity, they were of accuracy and eliminating parts.
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Nov 4, 2013 18:57
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Yeah, while rigidity isn't a huge deal for PCB milling, you definitely need precision. Complex circuits have spacings on the order of 0.005"; even for hobbyist use you need something that can hit 10 thousandths repeatedly, and .001 or better is ideal.
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Nov 4, 2013 22:13
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I'm all about CNCs and such, I've built one myself and have plans to build a much bigger/better one, I think they're awesome and fun and...if your goal is to make PCBs, why not just chemically etch them? It's pretty darn easy and requires minimal investment. You don't even need your own laser printer, you can get a pack of toner transfer sheets and get it printed at kinko's or wherever. Get some TRF foil to go with, and you can even make solder masks and silkscreens.
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Nov 4, 2013 22:29
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For me -- I'm all about dry processes. I try to avoid things that require large volumes of liquid and toxic chemicals as much as possible. Mills make a lot of dust and chips, but cleaning that up is a lot more pleasant than cleaning up a quart of spilled ferric chloride. I already have a CNC mill, though ... if I didn't, and I was only interested in making PCBs, I don't think I'd build one just for that purpose.
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Nov 4, 2013 22:39
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That's fair, I was just curious what the motivation was. I've done muriatic acid + hydrogen peroxide etching, and man, it's a cinch. You don't need a ton, either: put a few tablespoons of etchant in a zip log bag with your board and you're golden. Ziplocs withstand the etchant just fine, and make it so you need a lot less. Anyhow, carry on, just wanted to chime in there.  For what it's worth, the mill I currently have was actually designed for doing circuit boards. I liked the design, but wanted a bigger envelope (designed with a 6x6 envelope which I expanded to 12x12) so now of course the tolerance is awful as you approach the edges.  My current plan is a Joe's 4x4 built as a 2x3, and when I finally have enough shop space, I'll partially rebuild it as a 4x8 so I can drop sheet goods on there.
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Nov 4, 2013 22:58
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kafkasgoldfish posted:This is just a pcb mill, seems like solid tubing, milling and welding are a bit over the top. He could build the frame out of dimensional oak 2x2s and cheesy galvanized brackets from THD it'd be more than rigid enough. Yeah, the rods are all around 13". On this one axis with a 5" table, so I should be able to get 7". That's plenty for most of the PCBs I'd want to build. I'm in Canada, so shipping makes Misumi not really worth it (although they have an awesome system). I can and probably will get some extruded rails locally. And for making PCBs, I've used the UV exposure method, and I found dialing in all the timings to be an enormous pain in the hole. At the time, I was working a stupid amount of hours, so my time was more valuable than just sending it out. Ideally, I'd like to slap this together really quickly, and have all of the errors at least repeatable enough that I can correct for most of them in software. Basically I want to be able to design something and then press "print" and have a physical copy in a few minutes. I don't know how realistic that is, but it's good mech engineering practice in the meantime.
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Nov 4, 2013 23:53
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I don't know if this is the best place to ask but my brother wants to build a wood mill for his little cabinetry business. He needs a 1500x500x100mm envelope, Any suggestions on where to start? he'll need to cut all types of wood but nothing harder.
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Nov 5, 2013 22:10
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ante posted:Seems to me that the linear rods are necessary for accuracy. I could lower the platform like you say, but then there's nothing stopping the side-to-side motion or the up-and-down. Square tubing isn't exactly built to tight tolerances, so bearings wouldn't go over the surfaces perfectly smoothly. The rods seem pretty dodgy. I don't think you'll get the rigidity you're looking for, especially in the center of the range. There's also no simple way for a hobbyist to "true" the bearing surfaces. Much easier to use a flat surface and lap the ways against a reference surface (sheet glass is a great poor man's surface plate) before lapping the carriage against the ways.
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Nov 6, 2013 01:08
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Cakefool posted:I don't know if this is the best place to ask but my brother wants to build a wood mill for his little cabinetry business. He needs a 1500x500x100mm envelope, Any suggestions on where to start? he'll need to cut all types of wood but nothing harder. Id start with googling and ebaying a CNC router kit. I bet china makes one and someone imports it. Since tolerances are non existent for wood a lot of corners can be cut that cant be for aluminum. Id assume there are formulas for calculating the horse power you need for a spindle for milling wood similar to aluminum/steel/etc. Add a decent fudge factor to that because router bits are not ground to the same quality nor are they replaced as often as metal cutting bits.
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Nov 6, 2013 03:40
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CarForumPoster posted:Since tolerances are non existent for wood a lot of corners can be cut that cant be for aluminum. No, no, corner cutting depends on the tool radius.
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Nov 6, 2013 04:10
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Sagebrush posted:No, no, corner cutting depends on the tool radius. it's a fine line between clever and stupid
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Nov 6, 2013 04:12
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I like to keep one foot on either side, riding it with my balls.
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Nov 6, 2013 04:33
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Sagebrush posted:No, no, corner cutting depends on the tool radius.  
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Nov 6, 2013 08:18
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I'd like to make a small cnc mill. The parts I'd be playing with would be small, like 100mm x 150mm x 40mm. Most of it would be plastics but I'd like to be able to some light brass and aluminium. Most of the designs I've seen have much bigger areas and it seems silly to sacrifice rigidity and accuracy for space I'd never use. Anyone got any links to any examples of small mills?
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Nov 9, 2013 15:53
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Loving Africa Chaps posted:I'd like to make a small cnc mill. The parts I'd be playing with would be small, like 100mm x 150mm x 40mm. Most of it would be plastics but I'd like to be able to some light brass and aluminium. Most of the designs I've seen have much bigger areas and it seems silly to sacrifice rigidity and accuracy for space I'd never use. Anyone got any links to any examples of small mills? what's your budget?
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Nov 9, 2013 21:47
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rotor posted:what's your budget? Ideally about £500 or less. I've got a dialysis machine I can pull stepper motors from and MY GIRLFRIEND works in special effects so has a few machinist friends I can probably blag some materials from so I guess most of that budget can go to ball screws, controller and spindle. My rough idea is that by keeping the build area as small as possible it might make getting a steel or aluminium plate to use as a base for a gantry style design less expensive Loving Africa Chaps fucked around with this message at 16:19 on Nov 10, 2013 |
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Nov 10, 2013 16:07
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Cross posting from Cycle Asylum, I made some rubber parts for my motorcycle by CNC'ing a mold and casting them from liquid resins:Sagebrush posted:Finally finished a project I've been working on for some time. The modeling material is RenShape, in case anyone was wondering. It's a phenomenally awesome prototyping board that is also phenomenally expensive.
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Nov 12, 2013 05:03
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Those are fantastic.
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Nov 12, 2013 14:12
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That is so cool. I really regret selling my '71 CL350.
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Nov 12, 2013 15:28
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That's incredible.
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Nov 14, 2013 07:01
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That gives me so many ideas for other crap I could make. So cool.
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Nov 14, 2013 15:43
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