MetalMax Delta printer - belt catching on new linear rail - need advice please

[jrlederer]

Hello all,
If you'd have a look at the attachahed pair of images below, and then please answer the following associated question:

Will The idea presented by the Sketchup draft I threw together work, or am I (likely) overlooking something which will introduce motion planning errors or the likes? Does the number of teeth on the newly introduced pair of idler bearings (one nearby each end of the recently installed HiWin linear rails, in order to bring the belt path parallel with the carriage-delineated motion) have an effect that must be accounted for in order for the printer to maintain functionality?

Thanks, in advance. Hope everyone is having a great day and happy printing!

Kind regards,

Jonathan

P.S. - in the next post I have a little longer explanation in case anyone cares to know more. Moved it to a separate posting in order to not to waste anyone who's traversing the forums quickly

[jrlederer]

Detailed Information with regards to the above project:

Hi again,

I'm currently installing a set of 600mm linear rails (HiWin MGN-12 model) and have run into a slight hurdle and am in need of those more knowledgeable than I (pretty much all of you reading this I'm gonna guess ) to please have a quick look over the attached couple images to advise me as to whether or not the idea presented in the Sketchup CAD drawing I quickly threw together will work, to overcome the obvious major deal breaker depicted in the photo of my delta printer as it currently stands with linear rails attached but problem with the belt path. In case you can't tell, the belt is no longer parallel with the motion path and catches on the ends of the rails pretty much the entire length of travel and is, therefore, unusable until a new path for the belts is devised.

I was lucky enough to get ahold of the resident pro on this forum (mhackney) who was extraordinarily generous and helpful, and was nice enough to forward me his existing solution for this same problem. I'm looking forward to receiving that message. The idea I drew in Sketchup is what I came up with that I would have tried to implement in the event that I wasn't so lucky with contacting Michael. I'm just very curious whether that idea shown above would, in fact, provide a feasible work around for the problem with the belts and their indented paths caused by the thicknesses of the rails and carriages atop the existing extrusions, or if there's some fundamental factor I haven't accounted for that will cause a malfunction with printing if done in that way.

I thank you, in advance, for any and all suggestions which you might provide here, and thanks for taking the time to read this... Hopefully this may be of continuing reference for those interested in upgrading their delta printers to utilize linear rails as opposed to belt driven v-wheeled carriages.

Cheers!

--Jonathan

[DeltaCon]

Yes, I do not see why that would not work. You will probably need a similar construction at the bottom of each tower. That could interfere with how low your carriages can go, and therefore pose a limit to the max printable diameter. But for the rest it looks okay I think.

[bvandiepenbos]

Hi Jonathan,
Adding idlers to move belt path out should work fine. You will need one top and bottom.
However, the belt can not have a 90 degree twist like shown in your picture.
You will loose some maximum printable area using the linear rails.
Personally, I feel you will not see any noticeable advantage with the rails over wheeled carriages.
If your goal is to use the Smart effector, you could make an adapter to mount ball-studs on your Trick Trucks that matches Smart Effector ball spacing.

[DeltaCon]

Oops... did not notice the twist until Brian mentioned it...

[Xenocrates]

Additionally, you want the belt to be flat at the height it is above the linear rail. If not, over a travel of say, 400mm, assuming that you have a smallish gap between the pulleys and the rail, there is ~.7 mm of difference in the length of required belt, if you had a lift of only 5mm. At say, 10mm, it's nearly 3 mm of difference. Thus you will want to shim the pulleys out as practical to get the belt flat.

[jrlederer]

Thank you guys for the informative responses. I'll let you know how it goes.

Much appreciated.

Jonathan