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100 thou cut on a small machine like that is a big cut. Make sure the end mills you buy are also center cutting so you can plunge with them, since you aren't walking in to the workpiece from the edge. Also, 10-30k rpm is crazy fast for milling. You want to be working in the 200rpm-2500rpm range. http://www.southbaymachine.com/setups/cuttingspeeds.htm Brekelefuw fucked around with this message at 23:52 on Nov 23, 2015 |
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Nov 23, 2015 23:50
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This is the spreadsheet I use for speeds/feeds/power: (you'll have to download and open in Excel, unfortunately) https://drive.google.com/file/d/0B2oWFxMNwjKyQWpXWUZwOU0yZHc/view?usp=sharing You can't just plug numbers into the sheet though, you need to run some test cuts on any/every material you want to mill to see what your setup can handle. Start with a safe RPM, IPM and DoC and then vary each one until you have problems. Plug those into the spreadsheet and change the parameters until everything is correct for a given test, then see what sort of 'Required Power at Motor' it calculates. You'll now have a reference power not to exceed for 'unknown' operations. My Horrible Freight X2 mini mill can only handle about 0.4 HP (300 watts) before I get chatter.
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Nov 24, 2015 01:22
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Brekelefuw posted:Also, 10-30k rpm is crazy fast for milling. You want to be working in the 200rpm-2500rpm range.
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Nov 24, 2015 04:59
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mds2 posted:But my attempts in brass turn out like poo poo: Looking at the edge of the cut it looks like the cutter is smearing the metal. The chips coming off the cutter should be fine and sharp, kind of like splinters. Keep in mind that since your running a tapered burr the larger diameter is spinning at a much higher tip speed and is capable of clearing more metal than the very fine tip. You may be getting more into the area of stirring rather than cutting. A lot of times tools similar to what you're using are used for chamfering by engaging the tool against the work piece higher up on the tool away from the tip. Depending on your cutting strategy you might be better served using a ball endmill. The ball is wider at the base allowing it to continue cutting at the tip, but still get down into the nocks and crannies without gauging. McMaster and MSC both have huge selections of endmills in all kind of flavors. http://www.mcmaster.com/#8878a17/=zxzt9r (I took a guess that you need a 1/4" shank)
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Nov 24, 2015 06:17
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Brekelefuw posted:100 thou cut on a small machine like that is a big cut. Part of the problem with using that burr mill is that his SFPM at the tip gets infinitely lower and lower the closer you get to cutting at the tip, and there's almost zero cutting surface area at the tip to actually do any cutting work. Yes a ball mill should be a vast improvement, or a square end mill of a smaller diameter. Shapeokos were really designed to be running high speed carbide 1/8" dremel bits at 10k/RPM so that your SFPM gets closer to 200-400in/min. He should be side cutting with that burr mill, and he should be taking several passes. CrazyLittle fucked around with this message at 07:07 on Nov 24, 2015 |
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Nov 24, 2015 07:03
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mds2 posted:Yes one pass. Max depth was .1" I believe. This was a couple weeks back so I am trying to remember. I believe I was moving the spindle somewhere between 5-10 inches per minute. I am using a Variable speed Bosch Colt router. I think it spins anywhere from 10,000 to 30,000 rpm. The cutter I am using is in my previous post. OK, the two main problems are (1) you're way too deep, turning the spindle too fast, and/or moving too slowly and (2) the burr tool is probably going to make things worse than just using a regular end mill. I can't tell if you're trying to do V-engraving specifically or 3D profiling in general, but as other people have said, you'll benefit from a ball-nose mill. I would recommend a 1/8" 2-flute tool for milling brass. Carbide or HSS should both work fine. With your relatively low-powered machine that has a super fast spindle, you don't want to try to chew through the full depth slowly in a single pass. Instead, you want to be taking very light cuts over and over again. About .010 deep is a good place to start to ensure you have everything right. Assuming you use a 1/8" tool, setting your router to its minimum speed of 10,000 RPM will get you 330 SFPM, which is appropriate for brass. Calculate your feed rate based on the chip load: you want about .002 or so per tooth, so with 2 flutes that works out to roughly 40 inches per minute. Again, you're only taking off .010 per pass, so it shouldn't put much stress on the motors. Make your plunge feed rates about 5 IPM to avoid breaking the tool. For the burr, it's more difficult to calculate appropriate values because of the taper and the number of "flutes" with low relief, but start with the above settings and report back. So: 1/8" 2-flute ball nose 10,000 RPM 40 IPM feed 5 IPM plunge .010 depth of cut See how that works out.
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Nov 24, 2015 08:29
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Really really awesome info everyone. I think the machine is too under powered for what I am trying to do so that all makes perfect sense. It does seem to have a hard time pushing through the material, even at really slow speed. Any advice on spindles? I'm obviously WAY too fast for brass. I am trying to do V-Engraving and I used the free program F-Engrave to generate my files. One problem is I havent found a way to make it do multi-pass cutting. So I should probably try to find a different software. The reason I tried a V-bit is to get sharp corners. I will definitely try the settings recommended above with a ball nose mill. It'll be a few days before I can get a mill but I will report back.
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Nov 24, 2015 15:10
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Hm, my ball end mill got pulled downwards and hosed up a trial piece. And better yet the flexible coupler on the z axis came loose so the z-axis didn't want to retract right anyways. Definitely plunged too fast into that plastic for a 4 flute, but must have messed up getting the 1/4 to 1/8 adapter cranked down good too. Really wish I could find some more 2 flute bits that weren't relatively expensive but I guess I better just suck it up. Ah well, I got the X-carve Z axis motor mount dealie from Inventables recently, guess it's just time to go ahead and hook that poo poo up too. mds2 posted:Really really awesome info everyone. I think the machine is too under powered for what I am trying to do so that all makes perfect sense. It does seem to have a hard time pushing through the material, even at really slow speed. Any advice on spindles? I'm obviously WAY too fast for brass.
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Nov 24, 2015 16:20
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A Yolo Wizard posted:Could anyone recommend a basic set of end mills? I currently just have a 1/4" two flute up spiral from Home Depot for wood, and a cheapo set of 1/8" that I can't use because they don't have a 1/4" shank (if someone could recommend an adapter, I'd also appreciate it). I just want to cut acrylic, and later, carbon fiber (no thicker than 4mm) "drillman1" on eBay has a pretty decent selection of end mills, ball mills and such, and for pretty cheap. Always gets to me pretty quickly, too.
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Nov 24, 2015 16:51
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mds2 posted:One problem is I havent found a way to make it do multi-pass cutting. Rurin the same program multiple times with increasing depths?
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Nov 24, 2015 20:33
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Got the new z axis motor mount sorted out, promptly rammed the router into my fixture really hard because I didn't realize the new orientation of the motor would reverse its direction, and just generally hosed up. Turns out part of my problem is for some stupid rear end reason the z-axis lead screw is being pulled out of alignment, that is to say the actual carriage is sitting in tighter to the makerslide than where the lead screw goes through the mount does. Kinda suspected something like this was going on with the old z motor mount but wasn't really able to confirm it and didn't look too closely to begin with. So that'll have to be resolved ASAP before anything else can be done. mds2 posted:I am trying to do V-Engraving and I used the free program F-Engrave to generate my files. One problem is I havent found a way to make it do multi-pass cutting. So I should probably try to find a different software. The reason I tried a V-bit is to get sharp corners.
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Nov 25, 2015 00:27
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FYI Inventables is doing a Black Friday sale again starting shortly, X-Carves are $100 off and orders over $50 get a $50 gift card, including if you order an X-Carve.
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Nov 25, 2015 08:40
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I checked after the email and their site is hella messed up  Regular price 829 THAT'S TOO HIGH SPECIAL PRICE 829  Despite all that configured one and ADD TO CART = it becomes 1 sheet black ABS for 5.29  That don't look right so click remove on it = 404 error Plus a few other exciting weird links and text. Maybe I'll  again tomorrow
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Nov 25, 2015 08:50
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Parts Kit posted:If you want to go balls to the wall you could get a mini-mill and convert it. I think that'll have plenty enough oomph to do brass, though they're still pretty anemic when talking in even mild steel terms. Even with a mini mill conversion I don't think it would do what he's trying to do (plunge-cut & 1pass on a burr bit)
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Nov 25, 2015 09:20
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Parts Kit posted:What program is this again? F-Engrave. I found it right after I got my machine just by searching for CNC softwares. I think it is a pretty drat handy software and is pretty good for v-carving. It's free and he regularly updates it. http://www.scorchworks.com/Fengrave/fengrave.html
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Nov 25, 2015 15:17
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Hey that's cool - thanks for the link.
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Nov 25, 2015 18:41
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If you go here: http://www.scorchworks.com/ he has a couple other handy free cnc softwares. One of them converts images to usable G-code. But if you are looking to do sign making or things like that F-Engrave is great free alternative. I really wish it did multi-pass cutting though.
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Nov 25, 2015 18:49
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For me right now, a simple single-pass software that cuts some text without any online crap or other workflow (i.e. design in CAD then import, etc) is just what the doctor ordered.
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Nov 25, 2015 18:52
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Mister Sinewave posted:For me right now, a simple single-pass software that cuts some text without any online crap or other workflow (i.e. design in CAD then import, etc) is just what the doctor ordered. If you are just doing text, you can import basically whatever font you want into F-Engrave. I was looking for simple easy to use software too, and this fit the bill. One tip, if you are using a shapeoko: in F-engrave go into general settings and turn off "enable arc fitting" or you will gently caress up your poo poo.
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Nov 25, 2015 18:56
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mds2 posted:One tip, if you are using a shapeoko: in F-engrave go into general settings and turn off "enable arc fitting" or you will gently caress up your poo poo. Is that just G61 vs G64? The former being exact stop, the latter being constant velocity. If so, yeah, G64 can get bent.
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Nov 25, 2015 19:01
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Mister Sinewave posted:I checked after the email and their site is hella messed up
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Nov 26, 2015 02:32
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sirbeefalot posted:"drillman1" on eBay has a pretty decent selection of end mills, ball mills and such, and for pretty cheap. Always gets to me pretty quickly, too. I'll wholeheartedly second this. If drillman1 has kids, I'm pretty sure I've put at least one of them through college already.
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Nov 26, 2015 13:45
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So it seems like the x-carve has a crazy mark up on a lot of stuff. $75 for a power supply when you can get a 20 amp 24v power supply for $23 on eBay. Same goes for stuff like the $20 drag chain.
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Nov 27, 2015 07:28
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Also if you've got access to a table or panel saw I wouldn't really bother with the MDF wasteboard anyways. Unless they've bumped up the thickness from the 2 it's really flexible and mine came with a bit of a warp anyways. You can always drill holes and put tee nuts in where ever you need in a board of plywood, or if you've got the cash make fixture slots with more square extrusions. Fortunately you can de-select some of this stuff on the order page and get it elsewhere.
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Nov 27, 2015 14:42
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Just out of interest I specced up the 1m version without router, waste board, tools, chain, psu. $773, I don't know what shipping to the uk would be but after filling those voids from eBay and Amazon that's temptingly around £700.
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Nov 27, 2015 22:17
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I guess I'm a scrub, the sale on X Carve wasn't enough to make me pull the trigger. Their shipping rates to Canada don't help but it appears I'm just not ready to dive into a DIY cnc rig.
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Nov 27, 2015 23:06
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Speaking from experience - if you have the means to cut your own waste board for the X-Carve...do that. The 1m^2 board is 3/4" MDF, weighs about a ton and a half, and costs just as much to ship as it does to purchase. It's really nice, don't get me wrong, but that's the first thing I would have omitted if I'd been able to accurately DIY one.Cakefool posted:Just out of interest I specced up the 1m version without router, waste board, tools, chain, psu. $773, I don't know what shipping to the uk would be but after filling those voids from eBay and Amazon that's temptingly around £700. https://robosavvy.com/store/x-carve-fully-loaded.html Acid Reflux fucked around with this message at 00:52 on Nov 28, 2015 |
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Nov 28, 2015 00:32
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Acid Reflux posted:Speaking from experience - if you have the means to cut your own waste board for the X-Carve...do that. The 1m^2 board is 3/4" MDF, weighs about a ton and a half, and costs just as much to ship as it does to purchase. It's really nice, don't get me wrong, but that's the first thing I would have omitted if I'd been able to accurately DIY one. So like a table saw and a drill? It just needs to be a certain size and have holes right? Also you're going to have to buy a full 8 foot sheet at Lowes. So that might be hard to save money on
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Nov 28, 2015 01:06
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But you'd get two spoil boards out of it, and a bunch of scrap, right?
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Nov 28, 2015 01:08
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It's $32 for a full sheet of 3/4" MDF at Lowes. Plenty for two full 1m spoil boards, plus some nice big leftovers to break your first dozen router bits off in while you tune the machine.  The actual dimensions for the 1m machine's board are 940mm x 998mm. Here's a link to the GrabCAD page for it. There are a few holes that need to be somewhat precise - the slots around the perimeter, and the two counter bored holes on the center line - because they're used to fasten the board to the extrusions underneath and help keep things square. Other than that you can drill it any old way you like to suit your needs. Acid Reflux fucked around with this message at 04:25 on Nov 28, 2015 |
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Nov 28, 2015 04:23
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Acid Reflux posted:I don't know how the math would work out overall, but there's also a UK distributor: 50% more before shipping.
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Nov 28, 2015 14:39
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BiohazrD posted:So like a table saw and a drill? It just needs to be a certain size and have holes right?
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Nov 28, 2015 20:21
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Cakefool posted:50% more before shipping. Ouch. Sorry I mentioned it.
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Nov 28, 2015 21:00
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Z axis screw is definitely warped on the shapeoko. Has anyone tried the acme screw upgrade?
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Dec 1, 2015 23:48
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Parts Kit posted:Z axis screw is definitely warped on the shapeoko. Has anyone tried the acme screw upgrade? I have, it's quite nice. The way it attaches to the machine is better, the nut turns smoother, and in general it's a lot less half-assy. On the other hand, the 24v spindle is a hunk of poo poo, it never cuts anything right, and I'm reasonably certain the EMF it's kicking out is what's causing my machine to lock up and abort early. Time to see if inventables just ships me a dewalt mount or if I have to argue with them some more.
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Dec 2, 2015 08:30
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They started selling just the mounts a while back. I got one and it's solid.
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Dec 2, 2015 16:59
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Parts Kit posted:They started selling just the mounts a while back. I got one and it's solid. So they Mea Culpa'd pretty hard and are overnighting me a 611 and the mounting for the difference between the old spindle price and the new spindle price. Hopefully this will mean sweet sweet cuts this weekend.
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Dec 3, 2015 02:26
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Methylethylaldehyde posted:So they Mea Culpa'd pretty hard and are overnighting me a 611 and the mounting for the difference between the old spindle price and the new spindle price. Hopefully this will mean sweet sweet cuts this weekend. You're absolutely right about the EMF thing too - when they go bad, they start to leak bad juju into the rest of the system. The most common symptoms are gained or lost steps, and/or the motors twitching when the spindle is running but no commands are being sent through the controller.
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Dec 3, 2015 05:17
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Acid Reflux posted:There's been nothing but trouble with those 24V spindles from day one. You've probably seen all the posts about it if you frequent their forums at all. It's been a pretty big blemish on an otherwise great product launch, but as you saw, they've been pretty great about making it right. I lost two of them before I finally just grafted my Ridgid trim router onto the machine. Even after I owned up and told them I was pretty sure I was directly responsible for the second one's death (inattentive operator, horrifying machine crash), they still gave me credit for the price of the spindle. That's why I'm kind of a fanboy, I really think they've done their best to make good on a bad situation. In my case the entire GRBL system would either lose steps or come to a screeching halt and EndOfFile. On a stupidly long 3d carving job, it was super great. Hopefully a new spindle will go well with my nema23 steppers and let me get some useful cutting done. $1500 dollars later, my lovely Shapeoko 2 may finally be able to cut a box without crashing, failing, losing steps, slipping, or otherwise loving up the work-piece. I also plan to run the router's power cord away from the motion control cables, so I don't have to completely disassemble it, and so I don't have to deal with any other EMF related issues. I was half tempted to use shielded 20ga Cat 6e cables and using each twisted pair as a single signal cable, sorta like how balanced audio cables work.
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Dec 3, 2015 07:54
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I think there's a little more circuit juju after the end of the balanced audio cable, but that would be an awesome idea. Right now I'm anxiously awaiting a package of belts from China so I can get that z axis running. Inventables was out and I ordered the wrong size originally, ugh.
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Dec 3, 2015 21:40
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