Search found 554 matches

by Generic Default
Wed Dec 30, 2015 12:13 am
Forum: The Lounge
Topic: Magnetic vs. ball-joint rod ends [poll]
Replies: 54
Views: 17539

Re: Magnetic vs. ball-joint rod ends [poll]

I made some arms a while ago that are relevant to this thread. I put pictures on my Big Delta build thread but I'll repost some stuff here for convenience. IMG_1176.JPG IMG_1347.JPG IMG_1346.JPG IMG_1344.JPG This setup uses aramid/kevlar threads to hold the arms to the balls on both ends. The aramid...
by Generic Default
Mon Dec 28, 2015 2:59 pm
Forum: The Lounge
Topic: Check this out: bearing-free delta
Replies: 2
Views: 810

Re: Check this out: bearing-free delta

So it's sliding on napkins instead of using rollers? But the magnets are holding the carriage to the rail? Not so sure that's a step forward.....At first I thought it was a contactless levitating system but it's not. Also, I'm getting tired of seeing pencil thin arms on delta bots, it kills any rigi...
by Generic Default
Wed Dec 16, 2015 4:22 pm
Forum: The Lounge
Topic: Delta design reprap vs industrial
Replies: 23
Views: 4920

Re: Delta design reprap vs industrial

Yeah for most 3d printers, NEMA 17 and NEMA 23 stepper motors work fine. We are limited in speed by lack of machine rigidity and hotend back-pressure anyway. Plus, you can get NEMA 17 steppers for like 9 dollars each with the stepper drivers costing only a few dollars more on pre-made control boards...
by Generic Default
Thu Dec 10, 2015 7:44 pm
Forum: The Lounge
Topic: Magnetic vs. ball-joint rod ends [poll]
Replies: 54
Views: 17539

Re: Magnetic vs. ball-joint rod ends [poll]

I recommend nylon or acetal rather than PTFE; PTFE has a very low modulus and creeps easily. I used PTFE cups on an older arm setup. Eventually the ball and magnet will deform the PTFE enough to make contact with each other, at which point you lose centering and the low friction. Friction of a ~5mm ...
by Generic Default
Mon Dec 07, 2015 1:15 pm
Forum: Mods and Upgrades
Topic: 3rd magnetic arm upgrade
Replies: 24
Views: 7032

Re: 3rd magnetic arm upgrade

I'm actually getting away from magnets for arms. They pop off too easily, which is one of the main causes of print failures for me. If you had a reliable system that you didn't mess with, they would probably be fine, but I modify my printer so much that it causes problems. I've been doing a lot of P...
by Generic Default
Thu Dec 03, 2015 6:07 pm
Forum: The Lounge
Topic: Delta design reprap vs industrial
Replies: 23
Views: 4920

Re: Delta design reprap vs industrial

I think the rotational type of delta is plausible for printing. We would need a few upgrades and design changes: 1) All rotational axes based on back-to-back preloaded ball bearings. No play, tolerances <<0.001, rigid, long operating life. 2) Thicker CF tube arms with aluminum connectors and joint f...
by Generic Default
Mon Nov 30, 2015 6:29 pm
Forum: What are YOU making?
Topic: Tri Hotend
Replies: 160
Views: 44546

Re: Tri Hotend

That's a really nice looking effector Heffa! I just saw your design on youmagine, I was about to ask about a ring to clamp down the groove but then I saw the one you designed. Looks great! Let me know how it works; as long as the hotend stays mounted on the effector in a rigid way, everything should...
by Generic Default
Sat Nov 28, 2015 10:41 pm
Forum: What are YOU making?
Topic: washbear 3D printed 22LR pistol
Replies: 2
Views: 1290

Re: washbear 3D printed 22LR pistol

Looks like the best printed pistol yet, makes me wanna design my own similar to that. Putting chamber sleeves and barrel liners in these things can really make them into more functional firearms rather than 1 shot assassin pistols. He stresses not to use PLA, but I've been doing some high temperatur...
by Generic Default
Sat Nov 28, 2015 6:05 pm
Forum: The Lounge
Topic: Delta design reprap vs industrial
Replies: 23
Views: 4920

Re: Delta design reprap vs industrial

Those things are built for speed only. They have big AC servo motors that allow them to go fast while keeping decent positioning accuracy, but they still aren't as accurate as our deltas. Plus, they need a rigid, precise top base for the motors and arms. I think one of the main problems with the rep...
by Generic Default
Tue Nov 17, 2015 7:25 pm
Forum: What are YOU making?
Topic: Tri Hotend
Replies: 160
Views: 44546

Re: Tri Hotend

I'm uploading a video to youtube that I just took of a single nozzle print in PLA at 240C; I'll put it in this post when it's uploaded. I only have two of three nozzles on my Rostock right now. For now I just have a few more pictures. Heffa, the reason it's hard to find things about the Tri hotend w...
by Generic Default
Mon Nov 09, 2015 6:38 pm
Forum: What are YOU making?
Topic: DIY Mill Turn Center
Replies: 160
Views: 62729

Re: DIY Mill Turn Center

The lathe is a 4400 from sherline. I made custom stepper motor mounts and couplers, that was before I even had any measuring tools other than calipers so the mounts kinda suck. The lathe has been a PITA since day 1, and I realized early on that the tolerances and quality that go into making a lathe ...
by Generic Default
Mon Nov 09, 2015 3:57 am
Forum: What are YOU making?
Topic: DIY Mill Turn Center
Replies: 160
Views: 62729

Re: DIY Mill Turn Center

I was hoping to get stuff done this weekend but the cheap PSU wired to my CNC machines blew up. Not sure why exactly. I need to rewire all my things and fix my mill so it works reliably. Hopefully the smoothieboards didn't get fried when the PSU blew up, otherwise I'm screwed. Anyway, I got a few pi...
by Generic Default
Mon Nov 02, 2015 2:04 pm
Forum: What are YOU making?
Topic: DIY Mill Turn Center
Replies: 160
Views: 62729

Re: DIY Mill Turn Center

Some of the bigger parts of the machine need to be made from aluminum flat bar. The linear motion parts have to be aligned and machined without re-clamping, since they have to be accurate to within 0.001 inch over 12 inches or so. The surfaces need to be very very flat. Since I have a TAIG mill, I c...
by Generic Default
Sat Oct 31, 2015 9:31 pm
Forum: What are YOU making?
Topic: DIY Mill Turn Center
Replies: 160
Views: 62729

Re: DIY Mill Turn Center

The geneva mechanism never slips, and can be operated with a single stepper motor instead of a clamping mechanism (air, hydraulic, or solenoid) and a separate motor. Plus the repeatability is excellent. I can machine the entire geneva plate from one side using cheap aluminum flat bar. The live tooli...
by Generic Default
Sat Oct 31, 2015 8:43 pm
Forum: What are YOU making?
Topic: DIY Mill Turn Center
Replies: 160
Views: 62729

DIY Mill Turn Center

So over the last few years of 3d printing I've come to the conclusion that 3d printers are capable of making complex plastic parts better than most CNC machines can. With the exception of round parts. Anything that needs to be very round must be made on a lathe or other turning type of machine. Even...
by Generic Default
Sat Oct 31, 2015 7:53 pm
Forum: What are YOU making?
Topic: A Big, Rigid Delta (Picture heavy)
Replies: 26
Views: 7754

Re: A Big, Rigid Delta (Picture heavy)

I finally mounted one of my Tri hotends on the effector. Looks awesome. I wish I had more than 2 minutes a week to work on this thing, though! At this point I have the machine moving at standard printer speeds of up to 150mm/sec. Next, I have to wire the hotend and test print, then install all of th...
by Generic Default
Fri Oct 09, 2015 1:48 am
Forum: The Lounge
Topic: Additive manufacturing: Terrible tolerances
Replies: 29
Views: 5897

Re: Additive manufacturing: Terrible tolerances

Some metals like aluminum and brass don't really have a speed limit on machining. Others like inconel and titanium can only be cut so fast even with state of the art cutting tools. Some of the prints I've been getting recently look close to perfect, and come off the printer with flatness +- 0.002 ac...
by Generic Default
Fri Oct 09, 2015 1:19 am
Forum: The Lounge
Topic: Additive manufacturing: Terrible tolerances
Replies: 29
Views: 5897

Re: Additive manufacturing: Terrible tolerances

I think a printer with subtractive capabilities would have to be able to cut any plastic or any material you print. The main problem I think would come up is the maximum holding force. Normally, parts being milled or turned are clamped in a chuck or a vise. On a printer, you would have to rely on th...
by Generic Default
Sat Oct 03, 2015 4:48 pm
Forum: The Lounge
Topic: Additive manufacturing: Terrible tolerances
Replies: 29
Views: 5897

Re: Additive manufacturing: Terrible tolerances

Plastic part tolerances are worse than metal part tolerances because plastics are typically 50-200 times less stiff than steel. And they change with humidity and temperature a lot more than metals. And most plastics creep over time. Real 5 axis CAM software is typically expensive, but the majority o...
by Generic Default
Thu Oct 01, 2015 9:44 pm
Forum: The Lounge
Topic: Additive manufacturing: Terrible tolerances
Replies: 29
Views: 5897

Re: Additive manufacturing: Terrible tolerances

I'm actually not as pessimistic as you guys about the potential; I think filament type machines will max out at tolerances of around 1 or 2 thousandths. I think a lot of the current inaccuracy comes from the machines being designed and built on price points more than performance points. We're alread...
by Generic Default
Thu Oct 01, 2015 1:56 am
Forum: The Lounge
Topic: Additive manufacturing: Terrible tolerances
Replies: 29
Views: 5897

Additive manufacturing: Terrible tolerances

As the post title suggests, I've come to believe that all additive manufacturing methods and machine types are inaccurate. I've noticed this over the last few years, but I was expecting it to improve and it hasn't. Most of the tables I check say something like "+-0.008" for the first inch,...
by Generic Default
Wed Sep 23, 2015 1:31 am
Forum: The Lounge
Topic: Smoothieboards unreliable - what new controller to support?
Replies: 67
Views: 13842

Re: Smoothieboards unreliable - what new controller to suppo

That would be a nice feature to have. Not sure if it would work for my big delta because of the lead screws, but belt/cord driven printers would benefit from a stall-zeroing system. If the detector is reliable enough you could effectively use it as a closed loop system. If it can only detect that &q...
by Generic Default
Tue Sep 22, 2015 3:49 pm
Forum: The Lounge
Topic: Smoothieboards unreliable - what new controller to support?
Replies: 67
Views: 13842

Re: Smoothieboards unreliable - what new controller to suppo

Damn Arthur you have forum ninja response time syndrome . Smoothie Five-O be profilin' me. I have videos of the CNC stuff, I might have the original files on a camera SD but I transferred all my stuff to a laptop which has been unusable for a couple of months. When I was prototyping my Tri Hotend la...
by Generic Default
Tue Sep 22, 2015 3:06 pm
Forum: The Lounge
Topic: Smoothieboards unreliable - what new controller to support?
Replies: 67
Views: 13842

Re: Smoothieboards unreliable - what new controller to suppo

I'm still glad I bought the smoothies, there have a been a few problems with them over the year and a half I've had them but they work great most of the time. I think I'm the only person driving a lathe with smoothie, and I haven't seen any 4 axis TAIG mills with smoothies either. The stepper curren...
by Generic Default
Thu Sep 17, 2015 2:38 pm
Forum: The Lounge
Topic: Aren't statistics wonderful? Humor.
Replies: 33
Views: 5076

Re: Aren't statistics wonderful? Humor.

Nope. The company I work for still regards it as strictly forbidden. I suspect it's because the company has many locations across a number of different states and will hold their current position as long as it's illegal at a federal level. Either that or they think "Reefer Madness" is a t...

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