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My first reprap is complete! MendelMax...

Posted by PastaRocket848 
My first reprap is complete! MendelMax...
January 28, 2012 01:16PM
Hello! First post here. I just finished my first ever reprap project, a MendelMax with RAMPS 1.4. It took probably a month or two worth of intermittent work to complete, and went together VERY easily. I'm using Marlin for the firmware and the calibration was likewise very simple. I expected far more difficulty getting everything lined up and calibrated. I've included a youtube video of my first post-calibration print, a batman logo from thingiverse. I will post more as they come along.

Also on a side note: the J-Head MKIV-B hotend site (hotends.com) says you can't print PLA without a fan with this hotend, however I had no trouble at all doing so. The print in the video is using Ultimachine PLA (love the free samples!).


MendelMax first print video.
Re: My first reprap is complete! MendelMax...
January 28, 2012 01:21PM
Beautiful machine! Congratulations, you made a great choice in building a MendelMax.
Re: My first reprap is complete! MendelMax...
January 28, 2012 01:42PM
Thank you very much! It's been a great experience all around. Next up is a milling head and a laser attachment for PCB etching. This is exciting stuff! I thank all of you for all of the work you've done to pave the way for johnny-come-latelys like myself.

I do have one question to solve a nagging issue, though. It seems as though (after calibration) all of the prints are coming out very nice dimensionally (within .05mm, could be better if i did a couple more print-cube-and-adjust cycles, but for now...) yet even with quite a bit of extruder calibration (steps/mm) it seems like every print will have at least one or two "boogers" on the solid infill layers (usually the very bottom and very top layers) where the head seems to be dragging and causing the deposited material to clump up. It was way worse before the extruder calibration, and now only happens maybe once per part, but i can't seem to get them completely gone. Clear PLA from Ultimachine was far worse than the colored materials. it acted like superglue wanting to "stick" to the hot end and string around everywhere, clumping along the way.

also, how does one go about tuning out the little "bubbles" you get on the corners of 90deg turns (like when printing a test cube)? again extruder calibration has helped, and i tried tuning the retraction (0.9mm seems to work well), but they're still there, though very small. might faster printing help eliminate them? im at 30/60mm/s now.

can these be tuned out in the firmware or are they just kind of "the way it is"?
Re: My first reprap is complete! MendelMax...
January 29, 2012 11:08AM
May I ask where you got the parts for the mendel max from and what the total price was of all the parts?
Looking forward to your reply thanks

About the boogers, maybe the head is dragging on the surface due to unalignment of the bed? Also check your Z axis raise rate?
Re: My first reprap is complete! MendelMax...
January 29, 2012 08:45PM
That's a thing of beauty! Awesome job. You're making it difficult for me to stick with my large build prusa, haha...

Seriously tho, very nice.

Maybe you should attach a pic of these "boogers", hehe, that word!

Edited 1 time(s). Last edit at 01/29/2012 09:58PM by Skypuppet.
Re: My first reprap is complete! MendelMax...
January 30, 2012 10:12AM
i got the plastic parts kit from lulzbot. i am using that long enough to print my own x and y-axis, which will use 20mm t-slot for the y and 10mm (if i can find it, it not then 20mm) t-slot for the x (turned 45 degrees with eccentric-mounted v-groove bearings mounted to a printable carriage plate that engages the edges of the t-slot track). i will also ditch the threaded z-rods for real acme lead screws and nuts when i re-design the x-axis ends for the t-slot rails.

turns out the "boogers" were from a bed that is not flat. go figure standard 1/8" aluminum sheet is not flat, at all. i'm waiting on parts now for a new bed, made of carbon fiber plate, prusa pcb heater, and pyroceram top printing surface. the carbon plate isolates the heat from the abs-printed y-axis carriage, and also allows the spring system to be mounted to the plate rather than the actual build surface (pyroceram). this keep the total area of the build surface flat and free of obstruction like fasteners or bulldog clips. i may end up water-jetting some holes in the pyroceram if i can't figure out a way to mount it securely without them, but at least with the carbon plate they can be moved all the way out to the extreme edges of the build plate.

i've also done some work to make the design more "finished", in terms of wire managements and electronics mounting and what not. i am ordering the parts for 3 complete machines with my upgrades and will make kits and/or complete built machines available for order once they are complete and tested. should be no more than a month until they are all done. very exciting stuff!
Re: My first reprap is complete! MendelMax...
January 30, 2012 10:46AM
No aluminium sheet is a bit of a lottery, you need tooling plate to have specified flatness.

Isn't carbon plate was a relatively good conductor of heat? And being black will be a good absorber and radiator. How will that isolate heat from the ABS?

Re: My first reprap is complete! MendelMax...
January 30, 2012 11:15AM
i was thinking carbon fiber plate would make an excellent heat isolation material. i have a ducati with carbon pipes and i can hold my bare hand on them after running for hours and they're barely warm to the touch. that is, of course, carbon sheet laid around a mold and impregnated, but i wouldn't think a 3-4mm plate of the same material would be much different. they also make a honeycomb structure plate that is probably 90+% free air inside, which also may help. i'm going to experiment and see how it works. basically i just need a surface that will be rigid enough to serve as the mount between the build plate (pyroceram) and y-axis carriage (printed ABS), with the heated PCB in between. i figure i should use something to keep the heat away from the ABS.

right now i'm using an acrylic y-axis carriage with springs/standoffs up to an 1/8" aluminum plate, with a commercial heat shield on top then the pcb heater attached to another 1/8" aluminum sheet on top of that, spaced maybe 1/2" above the bottom aluminum plate. there is virtually no heat transmitted to the carriage area with this setup, but it is not flat.

EDIT: just got off the phone with the carbon supplier... it won't work. epoxy resin melts @ 160F. looks like it'll be aluminum tooling plate instead.

Edited 1 time(s). Last edit at 01/30/2012 11:27AM by PastaRocket848.
Re: My first reprap is complete! MendelMax...
January 30, 2012 12:01PM
A quick Google for thermal conductivity of carbon plate came up with 17, which is the same as stainless steel. Over a length of small cross section it is a reasonable insulator but from one side of a large thin plate to the other a reasonable conductor.

I use an air gap under the PCB and a heat shield made from corrugated cardboard covered with aluminium tape. Under that I have a sheet of dibond that is lighter than tooling plate but stiff enough. [2.bp.blogspot.com]

Re: My first reprap is complete! MendelMax...
January 30, 2012 02:25PM
where do you source the dibond material?
Re: My first reprap is complete! MendelMax...
January 30, 2012 02:57PM
I got it on eBay but you can get it cut to size from places like this: [www.cutplasticsheeting.co.uk]

I think it tends to be called Intrabond in the US and Reynobond seems to be another name for it.

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