Sheepdog published a new build:

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I moved the site around a bit,. try here.
http://griffinprinter.org/Griffin OS/index.php?board=6.0

 

While 3 years old and I do have some updates for it (been too busy working on the Pro), deltas really haven't progressed much since.

The only real big change has been 32bit, but most are still using Ramps, don't use Ramps on a delta, trust me. This is an easy swap to make, just change the controller mount. The other change has been more progress on magnetic rod ends. You will never max out the speed on on a delta using magnetic rod ends. I know people with Griffins that have been clocked on video at over 400mm/s, you cannot do that with magnetic ends. Their weight is an issue, as is the clamping power, they simply cannot hit the high speeds. As for the minor bit of slop, there are ways to fight that, we use o-rings on the Pro, simple, extremely cheap, and very light weight.

No matter how large the heated bed, you still can't really go over 150mm wide with plastics that need a heated bed. Shrinkage is shrinkage, the heated bed is just a bandage for the problem. There are ways to extend it, but for the most part, a larger bed just allows you to do more at once, not larger parts. Again, this only applies to those that need the heat.

You cannot just heat one section if you use a glass bed either, and even if you use thin glass, it will still need 400-500 watts to heat. That's a lot of heat being dumped out for a very long period. 24 hours? I barely consider that a break in print for our Pro XL. We've done lots of 30+ hour prints and several 72 hour prints. That's a long time to be putting out that sort of heat. A thicker chunk of glass will need 750 watts.

Keep in mind, that no controller is designed to handle that sort of power, so you will need a relay setup as well as a secondary power source. This borders on the idea that, just because you can, doesn't mean you should.

 

Beware cheap rails.
One of the reasons I used V-slot and we now use it for the pro models was because of the accuracy, Openbuilds tells you the specs and went through a lot of effort getting it to that accuracy.

The extrusion size is not what makes the printer stiff or a wet noodle. The length of the rail makes a difference because of the leverage it has on the frame connectors, you could put 80x80 and it will make little difference. If you want it stiffer, you need stronger frame corners, with a larger grip area.

Grab a rail and grip it at the end with your hand, now grab it at the end only using your thumb and index finger at the tip. You have far less control, and it's the same thing with a printer as it grows, you're reducing the grip and surface area. However, while not ideal, you still have yet to exceed what I consider safe for a Griffin (1000tall x 500 wide).

I'm not saying 20x40 will not help, I'm just saying it will not help nearly as much as you think as the rails are not the part that's flexing. Now, if you beef up the frame connectors, THEN the rails could become the give point, but as it stands, no.

 

You're welcome.

1. If you want speed, do not use magnetic ends. Take a look at the build guide for the Pro and you will see how we fight slop with simple o-rings..

2. I beleive the Rumba is just a Mega 2560, and not 32bit. You want a Smoothie, Azteeg X5, Duet or Beaglebone. Beware the latter, they can get pricey. If you don't want dual extrusion, the Azteeg is probably the bang for the buck. Also the smallest, easiest to hide and with good support.

3. A heated chamber can/will improve max print size and that's what you're describing, but they pretty much need to have a printer designed and built into it from scratch, the reason being, you will have a lot of heat in there. Cooling the hot end will be an issue for the hot end, electronics and motors need to be mounted outside, and you will end up with a very large box.

All of that, on top of the fact that parts expand, this is something many ignore in large printers until you experience it. At one show, we left our XL setup and because they disabled the air conditioner overnight, the printer grew by about 0.3mm, we had to recalibrate the Z height before it could print, and then change it back before the second print, and that was only a temp change of maybe 10 or 15degrees f. Inside a heated chamber it will change closer to 100degrees f, it will grow and the chamber needs to be able to compensate.

4. I like the mini-v's, while the std. Delrin work fine, I would like to try the polycarbonate ones, but they will be a tad noisier and probably do nothing in a typical delta. Do NOT use the metal wheels, they will slowly grind down your rails and absolutely make a lot of noise. You can sleep in the same room as a Griffin, you won't with metal wheels.

5. It's about surface and grip. Try bending some 2020 across your knee before you start messing with larger. and consider how much pressure the printer can actually exert. We have 1000x500mm Griffins running at 400mm/s and what flex the printer has doesn't significantly effect the print. Something smaller, at lower speeds will do even less.

By the way, choose your parts carefully, most printers and off the shelf parts are simply not designed for it, in fact most parts you find are actually only designed for running right around 100mm/s. Your extruder, nozzle size, hot-end type and frame really need to be carefully chosen, in fact, your pneumatic fittings, bowden tube and even where you mount the spool can play a part.