Building a LARGE corexy printer, and need advice.

Hello everyone! I'm new to this forum (and 3D printing as well), and was hoping I can get some advice on my very first project. I'm building a corexy printer (MAYBE an hbot) with a platform size of 600mmX600mmX1000mm. I'll be building the frame from 4040 aluminum extrusion. It's NOT the lite version. I got a fantastic deal on eBay for it, even with it being used. (45ft for $40.00). I paid more for shipping than the extrusion! Anyways, here's my question(s). What size nema17 should I buy, and are the 0.9 degree ones better than the 1.8? Should I get the new Smoothie board or go with the Duet with WIFI? Power source, ATX or the standard used in most builds? Should I go with with 3 screws for the z axes with one motor or more. I have a pretty good concept on how the corexy operates, but my main concern is the motors and the board for handeling the voltage/amps. I have sourced a 600mm X 600mm heatbed (silicone) that has the ability to heat the middle or entire surface (power is supplied by wall outlet and control switch). The lead screws I was thinking 12mm? Also for the x/y gantry rods, is 10mm stainless steel tubing sufficient? I was also thinking titanium (grade 5) rod/tubing as well. And yes your thinking EXSPENSIVE, but I found a supplier that has it for the cost of SS. Lighter is better, right? I know it's a lot of questions, and probably the most typical questions asked by a newbie, but any advice would be greatly appreciate. Thanks!

dump the ATX idea unnecessarily noisy things these days with relative low pricing of LED PSU LED PSU your question should be 12v or 24V think both your board option are happy with 24V just match the rest like motors, Hotend heater and bed.. get one with 3 outputs you may want to add some thing else later like a PI? or lighting.

Edited 2 time(s). Last edit at 06/27/2017 04:53PM by jinx.

With the mass of the gentry and he screws i would rule out NEMA 17 and directly go for 23. Also use 24V instead of 12.

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[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]

24 volt was going to be a definite. Can the boards handle nema 23's?

what about carbon rods, is it an option over 600 mm Tech2c attempt on the hypercube

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Can the boards handle nema 23's?

have a quick read through this for the duet and this

Edited 1 time(s). Last edit at 06/27/2017 05:13PM by jinx.

What materials do you intend to print?
What layer thickness do you expect to use?
Will you be printing large objects or lots of small ones?
What print speeds do you expect to achieve?
Single or multiple extruders?
Where will the machine be located?
Will you be transporting it anywhere?

Since you are new to 3D printing and to printer design and construction, these are all important considerations.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Really think about the questions the dentist asked.

Larger printers sound cool, but they are a lot of hassle just to have the print space you might not use. With larger prints come longer printing times, even if you use a hotend that can really pump out the plastic like the volcano, you would still be looking at days to print something that large.

Also keeping the nozzle level with the bed will take some some strengthening of the x and y axis and thats going to add weight. Just think about it, most people print with a layer height of 0.2mm and over 600mm the deflecting of the gantry will make a noticeable difference.

Really think about what you want to print and if you need the 600 x 600 and save yourself the time, money and engineering

+1 for all that advice, I have a 200x300 bed on a corexy and a 300mm circular bed on a Kossel Xl, I also designed and made a micro delta with just a 100mm circular bed and I can print 70% of the objects I want on the micro delta, using little space and even less power.

Duet can handle 2.4A and can drive nema 23's but you are talking about a very heavy z axis, especially if you want to use tooling plate to get it flat(ish) at that size flat is perhaps a bit optimistic. Sure you can use grid compensation to print on a slightly uneven bed and even set the central 200x200mm as the printing area for most prints but when you haven't used the rest of the bed for weeks you might wonder why you built it at considerably more expense than a smaller printer. It's a bit like buying a large van and rarely ever loading anything in the back.

Maybe you have large items in mind if so good luck we'll all help and will love to see the finished result.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

I really appreciate all the advice so far. Great information! My plan IS to print larger objects, so I do have in mind for the cost, and the challanges that come with building a large 3D printer. My plan it to make sure my frame and all the axes will be able to take all the loads, but I have lightness in mind when it comes to the x/y axes especially. My z axes will have a machined aluminum plate for the base (1/4"). I realize there will be some trade offs when it comes to accuracy and time as well. I was thinking of using stainless steel tubing (even titanium) for my x/y axes for strength, but my debate with that is the size of the rods/tubes. Should I go with 10mm or maybe a little larger. Lightness is the key right? Has anyone used titanium for their x/y axes? I know you may be thinking EXPENSIVE, but I have found sources that carry 10mm and 12mm rod//tubing for VERY reasonable prices. This would be a grade 5, which is VERY strong , light and rigid. Just to pick a few brains on that subject. The Duet board I think will be my choice when comes to the conrtrol. I've read and heard many good things about it. So any and all advice is appreciated. I'll be posting pics soon, once my build starts. I'm just waiting for all my brackets, screws, and nuts to arrive so I can get things rolling. Thanks !

I like to use rails for everything but they would be heavy at this scale. No experience with titanium, are you thinking of using rollers for your linear motion? If so can you get v slot titanium that can accept v rollers for the x axis? Y axis isn't a problem the rollers can run on the 4040 extrusion. Or do you have another scheme in mind?

Check this machine out its similar size [www.duet3d.com].

Edited 2 time(s). Last edit at 06/28/2017 10:45AM by DjDemonD.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

Consider making a build area rectangular 300x600 instead of a square. Shorter X axis will be lighter and will let you print faster...if you're impatient like me, printing large items slowly is exhausting

EDIT: I see you want to print big. I've been considering using titanium rods, however did not find any good sliders to go with. Titanium is strong but only half as hard as chrome so using regular bearings is not a good idea.

Based on this study PTFE (or maybe other polymer) bearing would cause no wear on titanium rod.

Edited 2 time(s). Last edit at 06/28/2017 11:59AM by newbob.

I would never consider rollers for any printer that needs precision. Personaly i would consider Igus Drylin W series.

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[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]

I just figured at that scale the weight of rails being steel would make for a heavy x-axis. If they make titanium linear rails then problem solved but I have seen any yet.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

I'd use rails for the Y and Z, and anodized aluminum tubes for the X rods. Larger the diameter the better for the span.
Drop the hot end between the X rods, and calculate the center of gravity for the carriage to be on plane with the center of the X rods for least deflection (moment of inertia).

Stay away from Titanium, unless you can get it hard anodized (type III). You can buy hard anodized aluminum rods that have a higher surface hardness than steel, and on par with hard chrome.
Cheap steel rods will be soft chrome and flake, cheap aluminum rods will have only type II anodize, which is 1/6th the thickness of type III and not hold up to wear.

Titanium > Aluminum > Steel is only true if compared by weight, by volume it's the other way round.
For tubes, the larger diameter the stiffer they will be, since aluminum is nearly 1/3 the weight of steel you can go larger to make up for the the fact the modulus of elasticity of aluminum is also 1/3 that of steel.
For reference, titanium's modulus of elasticity is about 1/2 that of steel, with nearly the same weight as aluminum. Titanium is also a bitch to machine, use speeds and feeds like stainless, and SHARP carbide tools only.
Nice thing about steel rods, is they'll typically be straighter and dimensionally more accurate than aluminum or titanium. By the way, always check the grade of steel, or temper (Al or Ti), it can have a big impact on performance.

Saw the video DjDemonD, and was impressed. Same build size I'm wanting to build. It's nice. As far as with x/y axes, I was thinking of using titanium rod/tubing with Drylin bearings. I have not seen actual titanium linear rails, while duing some research. I was thinking of using the Drylin bearing with the titanium rods. It would make a good combination for strength and lightness. I've sourced the titanium rod/tubing in a metric size, as well as Drylin bearings to work with them. The V-grove setup was another possible option I've been looking at as well. I was thinking of going with the Bowden setup. Trying to keep the weight down on the axes.

I was looking at the grade 5 titanium. It's MUCH stronger compared to grade 2. I've worked with it in the past (chainmaile) and it can be a booger to work with, especially when it comes to cutting it.

Hi yeah that machine is Ian's (deckingman on duet forum) chat to him he's printing with a diamond hotend with a second gantry above tethered to and following his x carriage with the extruders on it, at 250mm/s.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

I like the idea of such as large printer but want to add a couple questions along side the Dentist:

1. At 600 x 600 x 1000, where are you going to store this thing? 600 mm is almost 2 feet wide before you include any side panels or other parts. You may have difficulty getting a printer that size through doorways, even before you consider the weight.
2. Speaking of weight, will you every move it? If engineered properly for rigidity you are going to be looking at a very heavy machine. I am currently building an overly rigid mini corexy (thread coming in a couple weeks) and I estimate it to be 80 - 90 lbs when complete. Even without over engineering, your total weight may take a small team to move it up stairs or into a vehicle.

That being said, I think you should go for it if you believe you can do it. I would make sure not to rush your design process and get a solid plan before building it. Drawing the entire printer in a CAD software can also help avoid any major design flaws. I've been drawing mine for almost a year (ver. 31 on my 5th design).

Yeah, bigger is better, right? (not always). The frame is built from 4040 extrusion, not the "lite" type. 15 series I think is what it is (solid outer edge). I already have the frame extrusion cut. It weighs a little ove 60lbs. I cut the extrusion with my slide saw, using a high tooth count carbide blade. Cut like butter with silky smooth ends. I already have a dedicated place in the house where it's going to be set up. I plan on enclosing the frame and insulating it for heat retention and sound as well. I do have plans drawn up, but was looking into designing it on CAD. Looking at Autodesk/fusion 360. Have never used CAD before, so I know it'll be a learning curve for me (as well as this project). I will be contacting Ian to pick is brain andhow he built his printer. I bet he'll be a wealth of knowlege.

He has an extensive 3d printer blog well worth a read through [somei3deas.wordpress.com]

Edited 1 time(s). Last edit at 06/29/2017 03:25AM by DjDemonD.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

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eninja67
................... I will be contacting Ian to pick is brain andhow he built his printer.............

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You can PM me if you like - I don't bite

DD always has good ideas

work from inside out

size of bed ? Where will you be getting heaters for bed?
Do you have a small nuclear reactor to power them?

support -- 1.5m axis will sag? (1000 + mech room?)

belts -- long belts twist turn stretch?

mount for 5000m spool of filament? Big prints lots of feed?

big task for FIRST printer

Yes, it's going to be a big build. Most of the linear rails/rods, heatbed and screws have already been sourced. I've got the 4040 extrusion cut for the frame. It's OVER 60lbs. I have strength in mind. The heatbed will be ran off of a wall socket, with the board controlling the temp. I've sourced a dual zone heatbed as well. It'll heat the center, or the entire bed. About 170.00 for the whole unit, including the switchbox. That'll take some of the load off the board. Like cozmicray said, work from the inside out. That's part of my plan. I'm more of a "hands on" type person, who needs to see the actual part, and determine where things need/or can go. I love taking on a challenging projects.

Hey! How did this work out?
Did you get it done?

I'm dreaming of building a big printer, and am about 5 years behind your experience lol.
I'd love to hear what you learned along your build.