dual extruder questions

Hay
Quite new to the reprap world, but I know I defiantly want to build one as soon as I have the funds (budget aprox £400)

I know I want to build one with a dual extruder. I have been looking at some on ye old eBay,

Something like this:

[www.ebay.co.uk]

My only worry is how it will affect the build area. With the gap between the two heads being around 50mm. that would mean I would only be left with around 100mm on a 200x200 bed. Done as much goggling as I can handle on the topic and haven’t come up with anything solid to go by. Was thinking I would take something like a Prusa Mendel i2 frame and just extend it by 100mm, to allow both heads to reach the sides of the bed.

Anybody see any problems with that? Any general advice/links/brainstorming would be muchly appreciated

Thanks in advance

I have been struggling with two extruders on my OrdBot. The main difficulty is being able to adjust the height or Z calibration of each extruder independently of each other so they can set dead level. If they are not dead level the nozzle on standby can hit the print.

Reduced X axis width as you have mentioned is a problem. Having them one behind the other in the Y axis direction might be a solution depending on your printer.

Another problem I have found is oozing of the standby nozzle but increased retraction helps.

Here is my design to address the issue: [www.thingiverse.com]

Build a basic i3 with my extruder design. Then just use longer smooth and threaded rods for the Y axis to get full 200x200 print area. The rods need to be at least 25 mm longer. Nothing else has to be modified. If you do not change the rods your print area will be 200x175 mm.

You can calibrate the nozzle 2 relative height by adding paper strips between the lower or upper X linear bearings and carriage.

Edited 3 time(s). Last edit at 03/28/2014 09:23AM by jkoljo.

Thanks for the help.

placing the two heads along the y axit instead of the z is a good idea.

my only issue is where to get parts. i dont know anybody with a 3D printer, and i live in the sticks a bit. so i really have to stick with what i can get on tinterweb. iv seen vareious kits and bits of kits on ebay, mainly for an i3 design. and i do have plenty of time to plan before i actualy start building. maybe ill just get the frame panels first so i then have somthing to work from. then start making the rods.

Dual extruders do add a decent amount to the cost and definitely raise the learning curve. My site linked within my signature has a bunch of posts about dual extruders. I was luckey enough to be 1 of 10 people in the world working with printrbot on their production dual extruder setups. I started quite a while ago with their release of the dual extruder beta and now I have their production version. It will at least give you a bunch of info from the perspective of a new dual extruder setup.

There is quite a few different posts on there and a search spot to be able to find what you want easily. Your concern with the 2nd extruder taking up space is valid. I lost a little bit of x axis width when I added the dual extruder. What I did was extend my y and z axis to 17 inches (432mm) which more than made up for the space. I typically print a bunch of small things vs one large item.

Edited 1 time(s). Last edit at 04/09/2014 11:16AM by REPRAP SQUAD.

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If you went with a Bowden setup, you could move the heads a lot closer together, and save on carriage weight. As long as you are able to keep your hotends cool enough, you can have them quite close together, particularly with J-heads.

I have already tried that. I mounted two jheads together using a Bowden setup and the nearest I could get them was 50mm apart. However his means the bed width available for two colours effectively looses twice this distance i.e. it is 100mm narrower.

Hello,

Adding a second extruder is possible with modifying just a little bit the hardware of the machine. I would advice you to iterate: you could take in account the extra length needed in the machine design and start just with a single extruder. Then, when you are confortable with the printer and able to make nice print (it already takes a lot of time and effort), you could actually print your dual extrusion upgrade, decreasing the price of the 2nd extruder and getting to the issues caused by dual extrusions with everything else sorted out.

I would agree. Build a single extruder printer first and debug it. That in itself is a considerable amount of work.
Once it is working well, modify it to take twin extruders.