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  • tyrone shewlaces
    replied
    I built a 3D printer about a year ago and it all went well until I started trying to print things. I have several spools of different color of decent ABS filament, so I need to stick with that so I can use the stuff up, plus I like the characteristics of the material. But ABS is not the easiest to print. PLA is easier, so unless you need the ABS properties I'd start with PLA to get an earlier success rate.
    My build was around $300, but being a machinist, the cost was lower than it otherwise would be for the quality of the machine I made compared to the average reprapper. Regarding weight and rigidity and stuff, it turns out that both are very important actually. You don't need a 3D printer to be anywhere near as rigid as a machine tool of course, but the print head and the parts that move it around all have mass, move pretty fast and change direction constantly, which tend to cause vibration and it shows in the prints. Less mass in the moving parts (X & Y anyway) are better than more - the less the better as long as rigidity doesn't go down faster than weight.

    So long story longer... I stopped tinkering with my printer several months back because I started a big home project and simply haven't had the time. Once the house project is settled some, I will resume some focus on the printer. Despite not having an acceptable level of successful printing with it, the fun and education has still outpaced the frustrations so far.

    One major cause of my frustrations is the print head (hot end & filament feeder) I chose to go with. I DEFINITELY should have chosen a proven design from the start. I bought a QUBD and it didn't work worth a crap, so now it is heavily modified (not much of the original remains) and though it works much better than it did, it still isn't doing an acceptable job yet. It is kind of a copy of the one that comes on the makerbot, so in my opinion that is one to stay away from. Sidebar: Makerbot is steering away from ABS and toward PLA, so maybe this print head would work OK with PLA. That doesn't help me, but if you want to go the PLA route, that design might be OK. Look into it before buying.

    So anyway, I would do some research and choose a solid and proven print head design. Regarding the frame design, the Delta printers were just starting to enter the scene when I started my project and if I were starting today, I think I would go that route. Simple, open, light and sturdy (if done well).

    OK I think that sums up my main thoughts on it.

    edit to add: OOPS. One more big thought.
    Extruding plastic can work, but as was mentioned before it's not the only way to do it. Light cured resins are coming a long way and are supposedly as cheap as extruding for the material now if you go to the right sources ( http://hackaday.com/2013/10/09/3d-pr...want-uv-resin/ ). This is a much higher-resolution way of 3D printing and is probably the way of the future. It has a few limitations, but if your designs are right for it I think it would yield superior quality and less finicky results. Cost of home units you can just go purchase are probably comparable or only slightly higher. Home-made units are being posted about for folks to follow and copy as well, and it's possible that it could be cheaper to build than an extruder type printer.

    OK that's it.
    Last edited by tyrone shewlaces; 11-16-2013, 03:20 PM.

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  • schor
    replied
    I am interested in building a 3d printer, just for the fun of it. There's a group in my area that is building them, and using 3d printers to make most of the parts. I think I'll take another route and make mine of metal and sturdy enough to possibly put a router or milling head into it to it can be a printer and a carver.

    So far I am stsill just in the mental planning stages, hopefully in a few weeks I'll start on some drawings.

    I am interested in other peoples designs if others want to share.

    Steve

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  • vpt
    replied
    Hoffman is cheating. All his pictures are of the future. I bet he hasn't even built the machine yet.

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  • hoffman
    replied
    Originally posted by macona View Post
    Rigidity isn't much of an issue with these machines. There is not much mass moving and no cutting forces. The typical problem is just cheap construction. Using all-thread for leadscrews, stuff pinched together, no real linear bearings, etc. So the machines just kind of go where they want. Then there is the hot ends and about a half million different designs.
    This is a very popular hotend and my favorite:

    http://reprap.org/wiki/J_Head_Nozzle#Machined_Parts

    The "Hotend" is the part that the filament (Picture weed-eater line) is extruded through. Like macona said, there are a bunch of different designs but this one is a good performer and easily constructed by the HSM'er.

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  • macona
    replied
    Rigidity isn't much of an issue with these machines. There is not much mass moving and no cutting forces. The typical problem is just cheap construction. Using all-thread for leadscrews, stuff pinched together, no real linear bearings, etc. So the machines just kind of go where they want. Then there is the hot ends and about a half million different designs.

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  • Jaakko Fagerlund
    replied
    Now that delta build looks interesting enough I too have toyed with the idea of making a printer for myself, but the usual designs have been somewhat bulky or with lots of small parts and over-constrained system. But this delta, this is how I like it. Three independent and identical posts, some linkages and the printing head. Can't ask for more simple system!

    If anyone is going to build such a device or plan it, start a thread and I'm sure I'll be there to follow In the mean time I have to dig up more info on this and jot down sketches on paper and see when I have more money to buy all the stuff needed.

    I'm just wondering how much the weight would change if the plastic parts were replaced withh aluminum? It might provide more rigidity, so the parts could be made smaller in some places, but maybe it just doesn't matter at all except if the motors have enough power to guide the head in speeds exceeding what is needed for printing.

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  • KJ1I
    replied
    Hoffman -

    I was going to send you a PM and request the info. But since there has been a lot of interest, may I suggest you start a new thread here (rather than continuing in this one). I'm on board and looking forward to the build.

    And I agree about the volume of info out there. That's why I asked for help here.

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  • madwilliamflint
    replied
    Originally posted by hoffman View Post
    I'll just post a primer about what I know in this thread. There's info all over the net but it can be damned confusing. I'll focus on my delta bot since it's what I know.

    Would be great to have some more machinists on board with the project. Lotta folks who fool with these things aren't metal minded Plenty of improvements to be made by clever folks and there have always been some damned clever folks here!
    When I get to it I'll be sure to build a reasonable thread with the process as well.

    Thanks. o/

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  • hoffman
    replied
    I'll just post a primer about what I know in this thread. There's info all over the net but it can be damned confusing. I'll focus on my delta bot since it's what I know.

    Would be great to have some more machinists on board with the project. Lotta folks who fool with these things aren't metal minded Plenty of improvements to be made by clever folks and there have always been some damned clever folks here!

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  • madwilliamflint
    replied
    That's some good news. Yeah I'm sold. I'm a Christmas bonus check and a bit away from this. If you've got a link to the trailhead on this I'd appreciate it.

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  • hoffman
    replied
    Not even that expensive compared to HSMing. Can build one for about $500-$600 and do it in $20-$100 chunks.

    Knurls too:

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  • madwilliamflint
    replied
    Yeah I've got it in my head that some machinists are going to look at these things some day and say "thanks nerds, but we're gonna go ahead and make one of these rigid and production worthy."

    You've about convinced me to fit this in to my next available big project slot (after the home made drum sander and a 2x72 grinder, ugh.)

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  • hoffman
    replied
    Originally posted by DICKEYBIRD View Post
    Somehow I didn't remember you as a nerd. All 3D printer dudes are nerds, yes?

    More seriously, that is some fantastic stuff you're doing and it's encouraging to see "one of us" doing it successfully. I'd love to try it and your machine looks to about the right size but my 3D CAD skills are iffy at best. I've worked with it but it was very painful (older version of TurboCAD Pro) What CAD do you use?
    No, I'm still a grease monkey \o/ Just took a hiatus from welding/machining but continued to tinker

    I use Sketchup a lot which is a free download. Another one I use quite a bit is Tinkercad. Lotta folks poo poo tinkercad because it runs "in browser" and isn't real snazzy but it's easy to knock together a bracket or something quickly and just print it out. Look at some tinkercad tutorials on youtube.

    But yea, there is a weird divide between machinists and 3D printer folks but there is a place for both. 3D printing needs more machinists working on the machines in order to improve the technology. The more the merrier!

    I'm currently getting my shop set up at the new place and I'm focusing on machining some improved parts for these DIY machines.

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  • DICKEYBIRD
    replied
    Somehow I didn't remember you as a nerd. All 3D printer dudes are nerds, yes?

    More seriously, that is some fantastic stuff you're doing and it's encouraging to see "one of us" doing it successfully. I'd love to try it and your machine looks to about the right size but my 3D CAD skills are iffy at best. I've worked with it but it was very painful (older version of TurboCAD Pro) What CAD do you use?

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  • hoffman
    replied
    Originally posted by madwilliamflint View Post
    That's an amazing resolution progression from when I bought/built my "maker bot" which did nothing but suck $1500 out of my wallet, dozens of hours out of my life, and drive me into a murderous "wielding a ball peen hammer in a manner unintended by its manufacturer" rage.

    What's the rough time investment on that? Looks like it might be worth a second plunge.
    Just a few hours of desktop assembly and uploading the firmware to the controller. Not much to the mechanics of "delta" designs. Wiring is outlined pretty well here: http://reprap.org/wiki/RAMPS_1.4#Wiring

    Makerbot is the same thing in an overpriced shiny box... Sorry to hear it put a bad taste in your mouth. Kind of like selling a lathe and telling folks they could just fire it up and make fantastic model engines immediately...

    Getting one "tuned in" can be a bit fiddly but once dialed in they print pretty consistently. Best to find a brand of filament that works and stick with it. Quality is all over the place. Imagine ordering "steel" and having no idea about the machining characteristics but making parts out of it.

    Resolution is a trade off with time. Better resolution = longer print times.



    I get stuff like that off my machine and yes the threads were printed

    I've been working on stuff to get print times dramatically lower. This assy. was done in about an hour:



    As you can see, the resolution isn't as fine but it's a perfectly usable assembly and I'm working on better detail.

    Sure, the technology isn't quite ready for prime time yet but you don't see everyone with a machine shop in the basement either :O

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