New reprapper. Need bigger surface!

Hey everyone, a friend and I are planning on putting together a prusa Mendel II. The problem is that one of the objects we are planing to print OFTEN is about 8.5" long (about 220mm) and 2-3" wide. Most models of printers I have seen max out at about 7.5" (190mm). I want to know if I could scale up 1 axis? I am planning on using a heated bed so I don't want to scale up x and y or I will need 4 beds or 1 giant bed. I was wondering if I could scale up the width of the device. The triangles would stay the same length, just the track that the extruder travels on and the support rods would be longer to allow 2x 200mm heated beds. Is this doable? Also, if I CAN extend the bed to fit 2 heated beds and assuming I plan to use a RAMPS 1.4 set for electronics, will it support 2 beds? Can I wire them together in parallel and use a single thermistor for temp gauging?

Also, sine I have not yet touched firmware or software for a 3d printer yet, how would I tell the computer that I have a 200x400mm bed?

I am really excited to get this project together and if it means being stuck with no heated bed to get it scaled to 220x220, I will, but I would rather have a wide, maybe unique, 200x400mm unit.

Please help a new guy with a lot of questions make an informed purchase.

PS: I want to go with prusa Mendel 2 for part availability and price... I don't want to go maker it or something more expensive for a bigger bed...

PPS: the Mendel90 seemed like a good alternative where I could extend the bed that moves front and back instead. Let me know if this is better.

Thanks a bunch everyone!

Panterateama

In my searches for parts, I saw at least one oversized bed. It looked just like the red mk2, except it was 200x400 rather than 200x200. I couldn't tell you if it was meant to be larger in the x or y axis. In either event, telling the firmware about the bed dimensions is a piece of cake.

Awesome! Good to hear they have them ore built to 400x200... That mean less tricky wiring lol. I will have to look online to source one though... I'm in Canada so it's hard to find locally.

Any suggestions on the prusa, Mendel90 or A2Aprinting.com sells one called a "mixG1" that looks like a Mendel90 variant. Any ideas which would work best for this longer bed? Also will I need a bigger power supply or anything for the larger bed? Or is it just an adjustment in the firmware?

I'm a pc builder and tech support specialist by day and a 3d animator by night so I know both sides of software and hardware but not so great in electrical engineering lol

I would think the mendel90 type design would easily accommodate a longer y axis. The x axis could be lengthened too, but IMHO it would be easier to extend the y.

BTW, here is a link to the oversized bed. This is on eBay, but there might be others.

If you extend Y on Mendel90 by 100mm the bed would get 100mm deeper but the machine would get 200mm deeper. Better to extend X by 100mm, which would only make the machine 100mm wider (as well as the bed and the X bars).

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[www.hydraraptor.blogspot.com]

If I went with the prusa 2, could I also just extend the X? Making it wider? I was thinking of getting a kit without bars and just get a set of bars longer for the extruder track and support bars... Is this also ok? I think I could get the prusa much easier and cheaper here in Canada than the mendel90... Thanks for the help guys... I like to make an informed decision before I buy something this pricy... If I went with the wider bed, what would be the best software firmware combo (again, assume I am getting RAMPS 1.4 and MAYBE SD ramps kit later...

Thanks!

If you decide to double the X-axis on a Prusa you should consider moving up to 10mm rods on that axis at a minimum...

Mendel90 is a superior machine to Prusa i2 - especially if you are intending to lengthen the machine in X as nophead suggests.

The printed parts can't cost that much more. And the frame can be made of very inexpensive material with just a few tools. If you're intent is making large models then Mendel90 is the way to go.

Where are you in CA?

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- akhlut

Just remember - Iterate, Iterate, Iterate!

[myhomelessmind.blogspot.com]

Niagara region... Don't go to Toronto too often though but I assume that will be my best option

Thanks for the advice. Since this will be my first build I was hoping for the best documentation... It seems the 90 is a little sparse

Does anyone have any links for the mendel90 or prusa i3? They both seem very similar and able to support the larger bed but neither one has a good guide on the wiki... I still haven't figured out the github thing...

Thanks all!

[reprap.org]
[www.thingiverse.com]
[github.com]

Edited 1 time(s). Last edit at 01/13/2013 01:17PM by akhlut.

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- akhlut

Just remember - Iterate, Iterate, Iterate!

[myhomelessmind.blogspot.com]

Thanks for the links. I'm sorry if I'm a noob but what do I need to open the scad files and what should be the first few items I should look at on the github link? I hate to sound like a ninny but I wish thinks were just simple PDF docs lol

Scad files are read with openscad - Google it, download it and learn to use it. Almost everything I design to print I design in openscad.

panterateama,

you may be interested in this: [www.toronto3dprinters.com]

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- akhlut

Just remember - Iterate, Iterate, Iterate!

[myhomelessmind.blogspot.com]

You were right, I am Interested lol. Thanks!

I also found out that ekerstech (spelling?) is right outside of town for me so that helps with a local parts supplier.

So my current dilemma: no jumbo beds to be found so far in Canada... Is there any way or has anyone wired up 2 mk2 hotbeds? If so, what amperage should I look for on a power supply? I'm probably going for a good pc power supply.

If they can be wired together, how would I connec the 2 to a RAMPS set? Are there enough connections for 5 motors and 2 heathers and a hotend? I was also thinking about fans, the nice thing is with a pc power supply I can just get standard moles fans for cooling the extruder motor if needed.

Thanks again for the help guys.

Also does anyone have any examples of a double wide printer? I'm trying to figure out what the bar measurements would be for my x frame on an i3 or Mendel90.

Just a couple thoughts:

1. If you were planning on printing in PLA you would not need to worry about a heated bed. I've recently tested PLA prints with only blue-painters tape on the print surface (ie. no heat) and the prints adhered to the tape and printed just fine. If you are planning to print with ABS then, yeah, you'll need heat.

2. My recollection is that a single MKII draws about 10A. Rather than doubling-up MK2's, you could look into using custom sized silicone heatbeds. Kapton Heaters or TrinityLabs. I've considered tinkering around with these, but have not taken the plunge.

3. The length of your bars is really determined by your print requirements. The trick will be to ensure that your motors can adequately move your new, heavier print platform and that the chassis is sufficiently rigid. That's why akhlut suggested upgrading to 10mm smooth rods. But the chassis can be made of many materials. For example, check out the MendelMax 1.5 and it's extruded aluminum chassis. It uses all of the same electrics, but substitutes the more rigid extruded aluminum for the Prusa's threaded rod chassis. The extruded aluminum may more readily handle your larger footprint.

Good luck with your project!
Bobby

Hey bobby, thanks for the advice! I think I'm gonna stick to the mendel90 base model with the longer bars and maybe go with the 10mm for the x bars that support the extruder. I looked at the max but it was a lot more to source the parts in my area so prices became high fast.

I hope I can show off the final product after tax season. That is going to be our cash injection for the project.

A side question if I may: I am thInking of using a .3 or .35 nozzle with 1.75mm fil. Can I use a small nozzle like that with 3mm fil as it seems more easily found online and local? Or does 3mm need a .5 nozzle?

Can someone point me to a pro and con for the different nozzle sizes? I want the best looking prints, time is not an issue.

Thanks guys and gals!

You should be fine using 3mm with a .35 nozzle (I've seen that very combo offered on makerfarm). Just be sure to use a hot-end that is configured for that filament size.

I've built a Prusa and a Max and have opted for a .5 nozzle on both. My research indicated that the differences between .5 and .35 (concerning print quality) were negligible, but the .35 can be more finicky to setup. I have no personal experience with it though, so maybe someone else will have better info.

There is a wide version of the mendelmax posted on thingiverse. I know you have decided to go with a different model, but I thought you might be able to pick up a few ideas from this project. See here: MendelMax Wide

Good luck!
Bobby

[www.thingiverse.com]

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- akhlut

Just remember - Iterate, Iterate, Iterate!

[myhomelessmind.blogspot.com]

Dang pasted the wrong link! Thanks akhlut.

I am here to help.

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- akhlut

Just remember - Iterate, Iterate, Iterate!

[myhomelessmind.blogspot.com]

Lol thanks to you both! I will use this for reference ideas