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3d contouring with a ball/bullnose endmill shouldn't be difficult. Don't try to get it right to finish dimensions, leave some stock and just finish on a belt sander or grinder. Or hell, if it doesn't need to be too accurate just draw the profile and grind it all, if you've got a belt grinder.
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Dec 18, 2016 04:11
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Methylethylaldehyde posted:You can use carbide tooling regardless of what you're using it on. The little Taig will beat itself to pieces trying to use a modern coated carbide endmill as hard as they're designed to be run, but the carbide doesn't care if you're only running 5% of the design HP through it. There is a reason why ChinaBest brazed carbide turning tools are so popular, even little babby 1/4" ones, they work great compared to HSS. This. I'd honestly say that I'd rather use hss lathe tools and carbide endmills than the other way around. They aren't a cure-all, but a nice carbide endmill is vastly, vastly more rigid than hss, and makes cuts that would be a nightmare legitimately easy even if you can't use the additional speed. I don't have much excursive experience with bench top mills, but I'm betting that tooling is a much more limiting factor than you'd expect. As another poster mentioned: large depth of cut, low step over, and feed the hell out of it. You'll be horsepower limited at some point, but carbide will let you get closer to that point, especially with small endmills you'd have to baby otherwise. Disadvantages are cost and liability for chipping if you abuse it (so again: high doc, low stepover, high feed.)
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Jan 6, 2017 06:02
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Methylethylaldehyde posted:If you can afford the extra few bucks per unit, getting carbide is a huge improvement over HSS in almost every application. The only thing I can think of that it's worse at is chipping out if you oops it onto the shop floor or have the mill play for you the song of it's people and chatter bad enough to fret the edges or chip a corner. It's basically twice as good at everything compared to HSS, but costs twice as much. Insert tooling is a whole other beast, and is generally for high production runs on big VMCs, because a 3" solid carbide cutter would be ruinously expensive, brazed ones were legit awful, and you can do poo poo on an insert that would be a nightmare to grind on a regular helical endmill. Chatter, dropping it, and recutting chips are the big no-nos with carbide. HSS will complain about recutting chips, carbide will chip and explode. HSM helps with chip evac, but an air blast or light mist coolant is pretty much king. I do disagree about having one flute in the cut. One of the major advantages of the increased DoC is actually that you get multiple flutes engaged, which smooths out the cutting forces. That reduces resonance, prevents shock loading, improves surface finish, etc. oxbrain posted:There's a reason it's hard to find small indexable end mills. Inserts are never as sharp so you get higher side loading. They will never be perfectly aligned so you get worse finish in side milling. They can't helix around the tool so you get a big solid edge slamming into the cut all at once, which is terrible for vibration. They're great in large diameter tools where solid carbide would be really expensive and in big machines that can handle a big enough cut to keep several inserts engaged. The geometry also just doesn't work out. You have to sacrifice material to fit the inserts, and smaller endmills are rigidity limited. It gets even worse as you add positive rake, so surface finish suffers. Additionally, you can't fit as many flutes: up until about 5/8" you're generally stuck with one insert. Material removal is lower until it's rigid enough that you can properly abuse the inserts, or unless you're paying for the really fancy inserts and holders, neither of which is the case in the home shop. Bigger stuff, like the 1.5" CrazyLittle mentioned? Could be nice if you need a tool that big for facing or something. Smaller indexable endmills? Not worth it.
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Jan 7, 2017 05:51
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Methylethylaldehyde posted:If you only have 10% radial cutter engagement, you physically can't get 2 teeth in the cut unless the tool has like 6 or more cutting surfaces. Increasing depth of cut will get the upper part of the helix still engaged as the new tooth starts cutting, which would even out the cutting forces some. Yes, that's what I'm talking about, sorry if I was unclear. No, you're not going to get the tips of multiple flutes engaged at one time. Use higher helix tools to increase that effect. Though you can use way more flutes with HSM than normal. Good summary overall. Misses talking about chip evacuation, in my opinion one of the more important benefits. Thing to remember about point 6: it's only relevant if you're conventional milling. If you've got ball screws and are climb milling it works the other way. Either way the cutting speed change is pretty insignificant, usually just a couple percent at most.
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Jan 7, 2017 14:24
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Methylethylaldehyde posted:Yeah, the chip evacuation is another big plus, the first time I ran balls out HSM code on my Tormach, my buddies almost poo poo themselves over how far it was throwing the chips and the unending stream of them sorta spiraling around the part as it did an exterior profiling operation. Large pockets are trickier, but an air blast was enough to minimize the recutting. Pocketing is the hardest, definitely. Guessing you're already doing it, but spiraling in to make the biggest starting hole possible really helps (or even better, if you've got a tool changer: predrill.) The new dedicated HSM endmills have gouges up the flutes like a roughing endmill, but offset so you still get flat surface. If you've got a diamond wheel of the right shape probably wouldn't be too hard to grind some into a carbide endmill, that would also help with deep pockets, though you'd sacrifice some tool life. Airblast is pretty much always king, though, you're right.
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Jan 10, 2017 03:43
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Ambrose Burnside posted:Kinda outside the hobby scope of this thread, but is there some sort of really comprehensive software simulator that you could use with a Haas controller? Doesn't have to be free. My school has a bunch of Haas control simulators but they don't get used for much because the profs and techs don't think the dry run simulator that's on board is particularly good. http://www.immerse2learn.com/learncnc/haas/index.cfm These guys have a software simulator you could look into. No idea if it's any good, it's mainly intended for learning the control. Otherwise, CimcoEdit has a simulator, and I think GWizard has something too. Brekelefuw posted:I need to draw a bunch of different tapered rods in CAD using coordinates. If you've got the coordinates you've already done the hard parts and you could easily write the code by hand, or have excel do it. Use some concatenate functions to combine your coordinates with X and Z values, add in the approaches at the start and end, and presto.
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Feb 5, 2017 02:57
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Brekelefuw posted:I don't know g code yet 😭 Going to be honest: sounds like a perfect learning project. You can copy start and end code from whatever other posted code you've got lying around, and it sounds like you only need g01 linear moves to actually do the cutting. I'm less familiar with lathe code, but simple point to point stuff is really easy. If accuracy on tapers and curves is important you'd need tool nose radius compensation, but that's pretty easy to set up. Don't let the big lists of codes scare you: 75% of the time you use two, g00 rapid and g01 linear feed, another 15% is g02/3 arc moves, and the last ten percent is basically just T codes, spindle on, and work offset call.
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Feb 5, 2017 06:00
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Ambrose Burnside posted:The specific grievance is that they've got the physical simulator control panels on hand, so you can familiarize yourself with the actual control panel and enter codes and stuff, but the toolpath renders and graphics the onboard simulator outputs to give the user meaningful feedback is half-assed and doesn't emulate a lot of real-world conditions- like iirc it can't represent or predict most crash conditions because it doesn't factor for/care about fixtures or tooling or the physical machine constraints. You can't really do stuff like familiarize yourself with jogging around or a lot of the mundane work of the actual machining process. the immerse2learn thing Karia posted seems kinda like what's needed because it involves 3d renders of the actual machine doing actual machine things, the catch is we don't need or want software control panels because we have the real thing. Yeah, the simulators aren't very useful in my opinion, they just show the centerline trace of the tool with no other graphics or collision detection or anything, it's the same as the on-machine simulation. All it'll tell you is if the code actually runs, and maybe you can tell if it does something really wrong. The class I helped teach only used them for debugging simple manual programs. I only taught on the machine side, but we used the Immerse2Learn stuff to teach the basics of the control, CAM simulations for all the serious programs, and CAM simulations for all the serious programs. I seriously doubt there's a way to plug the physical ones in, but I suppose you could ask Haas. One other thing to note about the Immerse2Learn thing: the students can download it onto their computers, so they can play around at home. Also got some lesson plans, when I used it they were pretty hit or miss but they've probably improved.
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Feb 7, 2017 02:05
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Ambrose Burnside posted:Nominally-flat, but with large tolerances- i'd guess as much as 50-100 thou difference between the high and low spots of some pieces. Smaller stuff is tighter, but for bigger pieces the flat 'plane' the sheet is being raised or sunk to is strictly MK 1 Eyeball/"is it flat on the anvil"-level accuracy. I'd hypothetically be interested in engraving rounded or radiused stuff but then we're talking real Z-travel of an inch or less, more than the spring holder would take up, so I'm not worrying about that. 2L makes some pretty nice spring loaded holders. They're designed for rotating tools, not just scribers or drag knives, so you can get deeper engraving (the catch is that the slower you feed, the deeper it goes, so you have more process variables to control.) 0.4" travel, down to 1/4" shanks. There's enough preload on the spring that force doesn't vary that much with travel. Expensive, though. You can probably make your own fairly easily, it doesn't need to transmit that much torque.
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Aug 18, 2017 02:38
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What's the thickness on the Z axis plate? Looks pretty thin, and it's hanging way down below the gantry. Could you shift it up and shorten the gantry legs? Hard to see if there's anything else in the way from this angle. That could also let you make a more rigid connection to the Y axis screw, that link looks pretty flimsy. Seems like you're transmitting all the force through two pretty small bolts, that seems like a weak link, and the cantilevered arm is going to have a bigger bending moment because of how long it is. Of course, the importance of any of that depends on what you're cutting. If it's just foam you can get away with a lot more...
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Aug 30, 2017 03:24
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EvilBeard posted:that's 3/8" thick. I figured it would support it fine, once I get it adjusted up, so I don't have so much sticking down. I'm going with stock ball screw lengths so I don't have to trim and machine them down. I'm just trying to get all the pieces in their approximate places. I was planning on shifting the z axis up about 3 inches, that'll basically flip the ball nut holder, and I can use something thicker to get 4 bolts into into the z axis mounting plate. The gantry legs will be shortened to fit the proper height of the table. It's the next phase of the design. I wanted to figure out the gantry, because it's the most complex part of it. The y axis movement and connection to the table is pretty simple. Sounds like you've got it under control. It was hard to get a sense of scale, I'd been guessing 1/4", everything seemed pretty flimsy at that scale. 3/8" aluminum is much more appropriate for a hobby-level router.
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Aug 30, 2017 04:15
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Sagebrush posted:For the record, our Haas Mini Mill can produce 8 tons of force in each axis, so missed steps mean you did something really, really wrong Haas machines are all closed-loop via encoders and servo based. I can't think of a single professional level (anybody better than Tormach) cnc manufacturer that uses steppers. They're smaller, better accuracy with the encoders, better torque/power curves, and much, much faster. Cost and tuning are really the downsides, but the performance improvement outweighs it.
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Oct 2, 2017 17:17
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Out of curiosity, anybody ever actually use G2.1/3.1 (spiral interpolation) or any of the other weird interpolation stuff that Fanuc's got? I'm remember spiral, parabolic, involute, and spline off the top of my head. I've never had time to play around with them. Always figured they were just holdovers from the days before robust CAM to make handcoding easier. The program I helped with did a decent amount of manual G code, but it pretty clearly stressed that in the real world they'd probably never write programs from scratch, mostly just troubleshooting. I do a lot of coding, though, my code is maybe 50/50 MasterCAM/hand code. I get close in CAM, and if I need any real toolpaths beyond circles I start in CAM, but there's always too many little tweaks to get it fully optimized and too much macro-logic that needs to get added. As a quick example: I saved 0.5s per part on my current project by writing some macro logic for the first tool approach, based on whether it has the correct tool in the spindle (do XYZA move to safe position, then rapid Z to final depth) or needs to do a toolchange (do A move during toolchange, then XYZ move to final depth.) You can save a surprising amount of cycle time with that sort of thing sometimes.
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Dec 16, 2017 06:40
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This is going to get really nerdy and is only tangentially related to the thread. Sorry about that. Yooper's basically got this right: what all this does is transfer the intelligence further back in the chain. But it's nothing new. First the knowledge left the shop floor and went to the programmers when CNC got installed, then it went to the post-processor once CAM got good, now it's going to the CAM providers since they're making the post-processors. Even setting up that automated production line you're talking about? They probably hired another company to do it. There aren't many companies that have the ability to do that in house, they've transferred that intelligence to the distributors, robot, and machine tool companies that do turnkeys and integration work. I work on the machining-side of that sort of turnkey work. Our entire job is handling all of that process intelligence and handing the customer a black box solution. What I see is that there's a lot of processes and automated tools that are common-place in the sort of high-volume production work that I do that are getting simplified and more accessible for job-shops with smaller production runs, allowing sources of error to get removed and further out-sourcing process knowledge. It's not going to take too long for some of it to get to the point where it's accessible for hobby machines. A lot of them are the sorts of things Ambrose is talking about, albeit simpler. A few examples: * Obviously, CAM is getting better, vastly better. With more advanced simulation software like Vericut, you can actually be pretty drat sure that the code will work without needing to prove it out manually. Obviously doesn't account for tool length and part setup, but that stuff's getting automated too. It can already be pretty close to a black-box for simple programs. I do a ton of manual edits and optimization, but my job is pretty specialized, most people are going to be just fine with the CAM output provided they've got a good post-processor (which nowadays is just provided by the CAM company or distributor.) * Tool selection is getting more automated. How we do tool selection is a bit different: we just tell the tool vendors to give us the best thing they've got, they figure out the design, make whatever custom geometries we need, etc. Now job shops can largely do the same thing. Open up Kennametal's NOVO, or whatever Sandvik call their system, tell it what you're doing, and they'll recommend a tool. It can even handle customs. No need to get a whole bunch in house to do the testing or even hunt through catalogs, the manufacturer does that for you. Again, it's transferring the process intelligence back in the supply chain. * Machine setup is getting automated and checks are being added. Lots of machines can check tool lengths prior to actually running the tools (some of them can even do it while the tools are in the magazine so it doesn't impact cycle time.) That avoids crashes by making sure that tools are set up to the correct length. You could do that on even hobby machines pretty easily, just add a whisker switch or something, doesn't need to be a full-on tool probe. Coupled with automated tool-setup, and communicating the offsets to the machines via network or RFID chip, that variable can be largely eliminated. You can have a nice optical presetter that will refuse to let you set a tool up to the wrong length for... maybe $10k these days? Also, if you don't have it in your post processor already: output code comparing the tool offset to the nominal length, something like IF[ABS[#10001-120.]GT0.5]THEN#3000=1(TOOL 5 LENGTH OFFSET INCORRECT). It will save your bacon some time. * Datron's introduced a camera-assisted setup tool on one of their machines for probing routines. A number of manufacturers are introducing on-machine 3d simulation using actual tool lengths and workpiece models, some of them are even tracking machine motion live during the cuts to predict when there'll be a crash. https://www.youtube.com/watch?v=jzBM_lchKtg * Closed-loop production with automated gaging and offset input is getting cheaper and easier to do, Renishaw's Equator comparator, for example. MasterCAM even has a built-in probing system which can do measurements and make adjustments automatically, no need to mess around with macro code manually. * I haven't used them personally, but we do have tool-deflection sensors that can compensate live for that during a cut, and you can probably implement the same thing with one of the smart force-sensing toolholders you can buy these days. I think this is a more realistic expectation than continuous laser measurement of the part. There are machines right now that will take a picture of your tool for length verification. Use that to get the tool form, then you can reasonably estimate and compensate for deflection continuously from force measurements in the spindle or fixture.
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Dec 18, 2017 02:48
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I don't think there's any auto-relations for parallelism (though like Sagebrush said, it really isn't hard to just add the relation afterwards, and I find that most of the time vertical/horizontal relations or a dynamic mirror remove the need for that.) For perpendicularity, auto-relations can take care of it, but from a quick test only if the start point of the line you're drawing is not on the line you want to be perpendicular to, which I think is an odd design decision, but not hard to get used to. The thing to remember is that MasterCAM is a CAM package first and foremost. The sketching functionality is intended to copy geometry from a print, not for full-featured design. Solidworks is a design program, and it sacrifices some speed to enforce design intent and a robust feature chain.
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Jan 29, 2018 00:31
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I should have thought about that, considering how much I use the tangent-arc. And it turns out you can do pretty much the same thing to get parallel lines, so that's cool!
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Jan 29, 2018 01:18
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Eh, I think everyone feels that way about the first software they started. I still can't stand Fusion because it's not Solidworks (though it's been a few years, should probably try again), and I can't still can't stand Mastercam after two years because it's not Esprit. There are so many features I miss, going to Mastercam was like stepping back in time. Oh, for effective auto-pocket recognition and open chains...
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Jan 29, 2018 17:30
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Of course, on the flip side Esprit's got an interface that looked dated 10 years ago. It's pretty hard to just sit down and start doing stuff. Once you know what's where it's incredibly fast, but there is a learning curve, and not a whole lot to walk you through it. Still, there's a lot that just feels very well thought out in that software.
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Jan 29, 2018 22:06
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Ambihelical Hexnut posted:Something new-to-CNC hobbyists don't commonly realize is that your wood-cutting, high RPM CNC router will also start fires very handily, and the longer run times of milling/routing programs will lead to beginner laziness like "I better go check on something in the house for 45 minutes while this program runs". This is actually not just a problem for hobbyists or wood routers. Even professional-level metal cutting machines can burn down under the wrong circumstances, either when they're using cutting oil as coolant rather than a water-soluble emulsion, or if they're cutting the easier-to-ignite metals like magnesium or titanium. I've heard stories about people trying to use ceramic inserted cutters on titanium and burning their machines to the ground. One shop I did some work for had a guy die a few years back because he welded over a barrel of magnesium chips. Metal fires are nasty. This is not relevant to the home-shop machines which are the subject of this thread (I hope!), I just think it's interesting (and terrifying.)
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Jul 31, 2019 03:48
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Yeah, I think we require the fire suppresion systems whenever we sell a machine for magnesium or running cutting oil or something. Those crash compilations always disappoint me. Where are the videos of 2000ipm crashes straight into the top of a tomestone? If the pallet hasn't been ripped off its cones, it's not a real crash. Maybe ten years ago, one of our engineers was actually told to crash a machine. The designers had some predictions about how much energy was released in a spindle crash, but they wanted to verify it with emperical testing. So they sent him a machine and told him to start rapiding the spindle straight into the tombstone. So just remember: if you crash a machine, it's called stress testing.
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Jul 31, 2019 04:20
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It's not really a question of "can it mill aluminum" as much as "how fast can it mill aluminum." You can cut pretty much any material on any machine, it'll just be really slow, and you'll really need to know what you're doing. On small or router-style machines, you'll need to use smaller tools, smaller depths of cut, and smaller stepovers. What sort of plate thickness are you wanting to machine, how much material do you want to remove, and what sort of tolerances are you trying to hit?HolHorsejob posted:I'd be interested to see it if you succeed. I've cut a fair bit of aluminum on an othermill, but never a larger router. The table I did/kinda do have access to (arcpro 9600 plasma table w/ router kit) performed well on wood, but cutting aluminum on it sounds like a bad idea. Maybe I should give it a shot though, now that I have more time on my hands. Use a carbide tool. Aluminum doesn't really work-harden, either (maybe some weird alloys, but not 6061, that stuff's really easy to cut.) Chip evacuation is going to be the bigger issue on a router at high speed, and that can be settled with a shopvac or airblast (though be careful with the hot chips if you're vacuuming them into wood dust.)
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Apr 24, 2020 01:25
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biracial bear for uncut posted:You can use your last hole in one setup as your first alignment hole when moving setups. Maybe one program working off one edge datum, then the sequential programs basically calling X/Y zero the hole you locate off of in the subsequent setups. Rather than indicating in the hole every time you move, you can keep your drillbit down in the hole (plunged down past the flutes so the shank is in the hole), unclamp, and use the X axis to drag the bar over. You'll probably lose a thou or two every time because the hole's going to be slightly oversize, but maybe that's acceptable, and once you know that offset you can compensate for it if you want.
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May 15, 2020 23:25
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biracial bear for uncut posted:I was going to say this in my original post, but I know anybody with any industrial CNC machinist background would have a heart attack at the thought of using the positioning motors on a CNC to drag stock around (because they aren't designed with that in mind). I have ~8 years of industry experience. The motors wouldn't be the concern unless they're very under-spec'd. The only thing I'd be worried about is the spindle bearings: they're not designed to take static load. You'd need to minimize the bending moment by plunging the tool down as deep as possible into the material so you're running on the shank (that would also improve accuracy since you're not locating on the flutes.) Realistically, though, the load here is honestly pretty small, easily <20 lb-f assuming the stock is well supported on both ends so it's not bending the tool with its weight (note the linear bearings being used to support the cantilevered end.) Accuracy can definitely vary, but my understanding was that that dimension wasn't critical, and if it was you could use this method to get close then indicate the holes in. The more critical dimension (distance to the edge of the material) is pretty much exclusively controlled by the vise. I'll agree making a fixture plate is a better idea, though.
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May 27, 2020 18:10
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biracial bear for uncut posted:Most of the CNC machines I'm familiar with are large capacity routers that machine nested parts out of huge blocks of stock, so they definitely aren't meant to move 10' x 20' x 3"+ thick sheets of stock around (you really don't want to put that kind of load on the spindle anyway, shank attached or not). Even if it isn't steel, lumber and plastics get really heavy at that size.  Yeah, I understand your hesitance! Moving well-supported segments of bar stock short distances on a low-friction bearing is one thing, but yanking around a (conservatively) 1100lb piece of wood with a router spindle using a crappy single point of support is a flat "nope." I hope that person no longer works with you. EDIT: Uh, just to clarify: I mean I hope they got fired, not that I hope that they died. Karia fucked around with this message at 19:38 on May 27, 2020 |
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May 27, 2020 19:21
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Ambihelical Hexnut posted:Those example images appear to have been pocketed with an extremely small tool; look down at the bottom of the close-up, you can see cutting lines. Probably many hours of cut time at slow speed even with a larger area clearance tool helping. There are other ways to get a similar (but not exactly the same) look like v-carving or laser cutting a top layer and bonding it to a back layer. The material selection is important with tiny detail work too. Hard to tell, but I think the walls on that are tapered. They were probably using an engraving tool with a pretty fine point. That'll be a lot stiffer than an equivelent tip diameter and reach (though it introduces its own issues.) Though there are really fine corners up at the top, too... I guess there could've been some wonky 3d toolpath so everything can be cut with the small tip diameter? Not my area. Karia fucked around with this message at 02:22 on Jul 25, 2020 |
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Jul 25, 2020 02:18
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n'thing the "Solidworks is actually stable and good" sentiment. It definitely thinks in a different way than Fusion, though, so there's a learning curve. Ultimately I think it comes down to what you learn first: I started on Solidworks and Fusion frustrates the living hell out of me.
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Sep 22, 2020 03:41
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taqueso posted:My mech eng friends taught me solidworks circa 2006 when I worked at a company that used it. Then I moved on and didn't touch solidworks for years. I used alibre/geomagic for minor cad stuff and it was a pretty decent SW clone mostly. Now it's 2020, I got the $40 solidworks thanks to EAA. And to my surprise, the solidworks UI appears almost entirely unchanged. I was excited for new great features and cool UI improvements but I'm not sure there really are any. Honestly, I consider that a positive (and a big one.) They've got a user-interface and workflow that works really incredibly well for >95% of what you'll probably need to do. I'd rather they focus on small incremental improvements than break something that works just in the name of innovation. The changes they make are pretty small, but there's always at least one or two things that make me sit up and go "wow, that's actually pretty handy." And it's always easy to incorporate that into my workflow without breaking a decade of muscle memory.
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Sep 22, 2020 22:23
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taqueso posted:I don't feel like the interface is particularly good, but maybe I'm not deep enough into it. I had to manually bind shortcuts for things like sketch line and dimension. Maybe I'm doing it wrong? Nah, that's kind of how it works. There's a big learning curve with Solidworks, but it's not just learning where the buttons are and what the hotkeys are. It's also about figuring out how you want to customize the interface to suit your preferences. It's really expected that you'll remap all the hotkeys, change the toolbar configurations, etc, to whatever you're comfortable with. Solidworks designed around people who use it as a full-time job who will take the time to tweak it to their needs: the default configuration isn't supposed to be what you use all the time, just a starting point. Also, try mouse gestures. I find them really intuitive.
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Sep 23, 2020 05:22
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Figured this might be a good place to ask. Does anyone have any recommendations for a good dial-based tool offset gage (like this one)? I see a bunch of Amazon options, but it's hard to know how much to trust any of them. The goal is to train students with them (don't want to start out with the probes so they can get an idea what the offset numbers mean), so low-cost would be good since I guarantee they'll smash them eventually.
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Jan 25, 2021 22:15
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BattleMaster posted:There's always something I miss, I wasn't envisioning a permanent fit - at least, I don't expect there's an easy way to get it off once the shrink fit is done. I really was hoping that the set screws were an indicator of easy swapping Got a decent number drill bit set? If so, you can use the shanks as a cheap alternative to plug gages (nowhere near as accurate, of course, but better than nothing.) They're probably pretty accurate if it's an OK set. The gaps between the sizes are too big to judge accurately, but you can get much better resolution by using three of them like this:  Just play around until you find a set that just barely fits and you can trig out the size of the hole based on the nominal diameters. Better than using the ID section of calipers, at least.
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Jan 31, 2021 01:05
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sharkytm posted:They're usually less Makerspace, and more TechShop. Fully staffed, high-end machines, and big money. Yeah, and even with that TechShop still went bankrupt (RIP, you are missed.) That high monthly fee gets eaten up much faster than you'd expect: the machines can be very expensive to maintain, and letting non-professionals play around with heavy machinery shoots your insurance costs through the roof. Seriously, insurance costs were one of the top reasons TechShop folded. The other main cause was massive embezzlement.
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Mar 31, 2021 00:58
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It's kinda weird that it's the same on all three machines, that suggests against backlash and other machine issues in my mind. Is it the same 1/2" endmill assembly on all three machines? Did you get a batch of reground tools in (or buy a bunch of bargain-bin rejects)? Or, if you're actually using cutter comp, recalibrate your tool probes/presetter recently? (And even if you're not intending to use cutter comp, check the programs to make sure that there aren't any G41/G42/Hurco-equivalent commands in there.) Alternatively, could it be tool deflection? If you've got identical tool setups and the spindles are very similar that could repeat pretty well between machines. 2 thou would be a decent amount of surface location error for a 1/2" cutter, but not impossible, depending on how much tool extension you have. How much stock are you leaving for your finish pass? EDIT: Read a bit more carefully. It'd only be 1 thou of deflection on each side, which is pretty reasonable, but it's interesting that one side is long and the other side is short, that suggests against cutter comp issues as well. Are those dimensions consistent across the entire length of the part? Karia fucked around with this message at 02:12 on Jun 24, 2021 |
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Jun 24, 2021 02:08
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 Sounds like you've got your head on straight about what you're checking. Vise squish was my other guess, but running the numbers on that for a 1.25" tall block of 4140 seems like it'd be way less than a thou. New tooling doesn't always mean much, but given the specific error you're seeing that doesn't seem like the problem. Last guess before I stop playing backseat machinist for the evening: I'm sure you've already checked it, but is your measuring equipment OK? Nobody dropped your 2" mics, right?
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Jun 24, 2021 03:10
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Last thought before going to bed: stress relieving causing the part to distort? It'd be weird to have that just make the part smaller and not bow it since you're presumably only doing one face in this operation, but internal stresses can do seriously wacky stuff, and could absolutely cause the part to shrink in only one direction. Try mic'ing the dimmensions immediately after they're cut (allow time to cool down to 68F if necessary, of course.) If that looks OK, then try shifting the finish pass to the very end of the program if it's not already there and see if that changes anything (not just the spring pass! Spring passes don't do anything if the material's already shrunk, obviously.)
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Jun 24, 2021 04:47
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Fanuc actually does have a specific G code command for spirals, weirdly enough. G2.1/3.1, depending on which direction you want to go. I know I read about it a few years ago in one of the Fanuc G code manuals, I'd have to dig back through my archives for more details. Not sure if it's something you need to buy an option for. The below blog is the only evidence that it exists I can find via google, but I swear I'm not making this up: http://cncprograming.blogspot.com/2011/06/how-to-make-spiral-interpolation-g021.html
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Jul 9, 2021 03:11
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If this is for non-commercial work, you can get a personal use licence for Fusion. They recently did add some ridiculous limitations to this (IIRC you can't do toolchanges and some other stupid restrictions), but for one-offs it's still probably your best bet. https://www.autodesk.com/products/fusion-360/personal Or if you're a student then you can get the full software for free (one year licence but you can just get a new one when it's over.) https://www.autodesk.com/education/edu-software/overview
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Aug 13, 2021 05:20
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NewFatMike posted:Psh, like nobody has put a piece of stock in their mill spindle and a cutting tool in their vise before Just call it an inverted VTL and double your quote because you had to use such a specialized machine tool.
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Oct 27, 2021 02:33
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I had a dream once where I popped a couple advil before heading into the shop. My boss asked me if I was on drugs, and then sentenced me to death by hanging. By getting pushed off the top of one of the Haas machines.
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Oct 28, 2021 04:22
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biracial bear for uncut posted:Had to be a UMC750 or something, right? Are the TM/VF machines even tall enough for that drop to kill you? MDC. Pallet changing vertical, predecessor to the MDC-500, which was predecessor to the DT-1. Probably the least reliable machine I've ever worked on. We had the prototype, serial 1. It was also their prototype for the highspeed toolchanger that they put on the SS machines. If you toolchanged at 100% rapid it would throw the tool.
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Oct 28, 2021 22:09
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meowmeowmeowmeow posted:They also rip through aluminum injection casting materials that have high silica content or any other highly abrasive no ferrous materials. Seriously, this is no joke. I've run 7" 20 insert PCD facemills at 8000 RPM, 500 IPM. It is absolutely astonishing what you can do with it. And they last forever in cast Al. I was setting up a new turnkey for a customer, transferring an old process they'd been running onto new machines. Some of the tools they gave me were spare PCD cutters that had been sitting in the rack for 4 years because the original tools had cut 300k parts and were still going strong. I honestly don't understand how PCD tool vendors make money on this stuff: it's pricey, but it's not that much more expensive than an equivalent carbide tool. Then my boss stepped down just slightly too far, the inserts cut like 5 thou into one of the tool steel fixture clamps and they were all shot. That was like $3000 down the drain, and I got to spend another hour aligning the new inserts.
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Nov 30, 2021 22:07
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