Hi I have recently bought a K8200 printer and would love to have a 400mm square print bed, would it be possible to have the .stp or .igs file for the BED SUPPORT plate and the BED PLATE itself so I can scale the part up.
Also does anyone know how to extend the motor run from 200mm to 400mm in the Repetier-Host software, as currently I am unable to get the X and Y motors to move more than 200mm.
Thanks All
For the motor range just check your printer settings in repetier.
There you set the print bed size, which is actually X and Y max.
Sounds like a very cool project but a lot of work as you would have to rebuild the complete machine.
Yep, sounds nice.
But having a 400mm by 400mm bed means to scale the whole frame to amout 1000mm by 1000mm.
And i think a different approach for the x and y carriage would fit better then.
It’s like building it new from scratch … 
Hi thanks for the replies,
Yes im going to scale up everything to suit and I understand that its basically a brand new build.
But obviously the main concern is to get the bed to move more than 200mm. I have tried to extend the bed by altering the bed settings in repetier to 205mm just to see if the bed will go an extra 5mm but when I home the bed and try to travel 205mm manually, the bed stops at 200mm. However the repeater software displays 205mm. Im no expert but it looks like the firmware on the control board is stopping it moving further unless there is another option I don’t know about.
I’m new to this but I have read that other people have extended their printer in the Y axis, so it must be possible. I’m probably missing something obvious.
I’m using the latest Repetier Software and have tried different versions but I cant get the bed to move more then 200mm in the X or Y axis.
Thanks for your help in advance.
Open your Firmware in Arduino 1.0.6. and search the configuration.h tab for these lines:
[quote]// Travel limits after homing
#define X_MAX_POS 200
#define X_MIN_POS 0
#define Y_MAX_POS 200
#define Y_MIN_POS 0
#define Z_MAX_POS 220
#define Z_MIN_POS 0[/quote]
I just searched for it, i did’t try it out. Bet it works.
After you uploaded the new firmware to your printer, you need to load failsafe to get the changes take effect.
Look into this topic for more information:
viewtopic.php?f=50&t=13159
Did you already look out for other cartesian printers which are this big? i just wonder if there is a maximum belt length you should’t exceed. A very long belt tent to vibrate more easy than a short one.
Thanks cantax, it worked a treat!
As for looking around for other printers i did, but for the price of this one and the obvious support for it on this forum, i thought i couldn’t really go to far wrong even if i couldn’t make it any bigger.
If anyone has .stp or .igs files for the BED SUPPORT plate and the BED PLATE itself, that i could use that would be great!
Thanks again
You didn’t understand me right. Well, thats probably my fault because of my bad english.
What i meant was: Look out for other printers. Not to buy them, just to look out for the technique they use for traveling the x and y axis. If they use belts like the k8200, just double the length, then it’s ok. A Design that is used by other printers will work.
But if there’s no other printer on the market which does it like you want to build it, you need to ask yourself:
There are many printers out there using bowden extruders instead of direct extruders. The idea is to minimize moving weight. As you can see, a moving bed is not the best choice. If you double the length of the belts which move the bed, best thing that can happen is print quality won’t decrease. It will absolutely not get better.
Question is: Is it still working good enough or are the belts going to vibrate because of the doubled length, causing the accuracy of the bed movement going down too much to get good print quality.
When extending the travel lenght of X and Y i would suggest using a more sturdy construction as stresses are increased and tolerances might be lost in the slight stretching of the belt and swaying of the entire construction when moving at higher speeds
I would recommend upgrading the 8mm shaft to 15mm and the 12mm shaft to 20mm - linear bearings for these measurements can be bought from SKF (and also many other bearing suppliers)
Also upgrading the motor mounts for stability and switching the rubber belts to metal roller chains and adding a sprocket instead of a pulley to the motor shaft, adding chain guides and tension capabilities to reduce the amount of potential vibration in the roller chains.
I believe these upgrades are sufficient to be able to run the machine on the increased area you want, though i am not certain the motors can handle the extra weight
If I can throw in an opinion it would be to use the K8200 to learn about 3d printing and how the machine works before redoing it. I am sure you are more than capable in pulling it off. If I were to build a new printer, it would not be a larger version of the K8200 because of some inherent limitations. Many clever people on this board have overcome many of the limitations, but the biggest one that is unavoidable is the bed moving in x-y.
If I were going to the trouble of doing as much work as you plan, I would start with a different design. I am not denigrating the machine. I like mine. It been fun tinkering with it. Knowing what I do now, I would never build new one from scratch. I would use what I have learned and build a different design.
Hi,
Any progress on this?
A quick search on the internet shows me larger printers are all of the h-bot type.
I am curious if you can extend the K8200 to 400/400 dimension.
Hi,
Im already extending my K8200, the “Z” axis has been extended to print 370mm, and uses twin steppers and trapizoidal leadscrews.
I have one carriage assembly finished, this holds 2 hotbeds, halfway through the second carriage
I will then bolt the two together, each has a stepper fitted and has 2 guiderails 8mm diameter.
The frame sections are cut to length (Alfa profile) and are ready to bolt together.
The carriages and hotbed mounting plates including the sub plates have been laser cut (Im luck we have one at work)
I envisage that i will need to drive the “X” axis as well as the “Y” axis in the same way as the “Z” ie 2 steppers for each axis.
Im also using GTA2mm belts with tensioners fitted.
Sounds interesting!
Can you post some pictures of your progress?
No problem, how do you attach pictures so that they show in the actual post please
Please provide links to the picture, the forum does not allow picture uploads.
You must upload them to a picture hoster or dropbox and post a link
Hi All,
The mods for the K8200 are shown here
s1381.photobucket.com/user/jan254959/library
There are pictures of the work in progress X and Y axis extention to 400 X 400 print area
And the Z axis extension to 370mm print height (The leadscrews are 500mm long)
And a couple of pictures of the print quality after the leadscrew mod (No Banding 
)