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snowygrouch

Throw away your short belts - direct drive.

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Hey guys,

really want to do this modification, I am printing the brackets as I type, and have the couplers, 8mm rod and some awesome new pulleys.

The mechanical part of this mod is easy, but i want to put the Y axis motor on the back of the machine. I was wondering which wires i would have to swap to reverse the voltage in the motor, and where to swap it? by which i mean do I remove the wires from the plug or cut the wires and re solder or use bullet connectors etc?

Any help would be greatly appreciated and pictures would be even better!

Thanks

Bob

 

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You can pop the wires out of the connector, no soldering required. On the side of the connector there are holes in the plastic that small metal tabs hook into. If you use something sharp you can push down on these tabs and then you can just pull the wire out.

I'll have to check on the wiring order because I can't quite remember (or someone else will likely beat me to it as I'll be heading to bed soon). I think I changed it like this 1234 --> 3412 but I'm not 100% on that.

 

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Hey guys,

really want to do this modification, I am printing the brackets as I type, and have the couplers, 8mm rod and some awesome new pulleys.

The mechanical part of this mod is easy, but i want to put the Y axis motor on the back of the machine. I was wondering which wires i would have to swap to reverse the voltage in the motor, and where to swap it? by which i mean do I remove the wires from the plug or cut the wires and re solder or use bullet connectors etc?

Any help would be greatly appreciated and pictures would be even better!

Thanks

Bob

 

On the plug at the end of the wire from the motor. Swap the left pair of wires with the right pair but keep the order of each pair the same.

 

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Another option is to change the firmware.

Umbau 2

#define INVERT_X_DIR false // for Mendel set to false, for Orca set to true, Ulti direkt false

#define INVERT_Y_DIR true // for Mendel set to true, for Orca set to false, Ulti direkt true

#define INVERT_Z_DIR true // for Mendel set to false, for Orca set to true

#define INVERT_E0_DIR false // for direct drive extruder v9 set to true, for geared extruder set to false

#define INVERT_E1_DIR false // for direct drive extruder v9 set to true, for geared extruder set to false

#define INVERT_E2_DIR false // for direct drive extruder v9 set to true, for geared extruder set to false

 

 

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So Fellow hackers,

I did the modifications over the weekend and the prints are looking great!

However, my stepper motors are getting really hot, to hot to hold onto. Is this normal?

Up til now I have never really paid much attention to any heat the motors give off as they were tucked away in the case, so I don't know what is normal!

I took great care aligning the brackets and Motors and visually when in operation nothing seems to be off centre or out of line!

I have ordered some heat sink fans (as per Callum's guidance) my next question is how are you folks powering them?

Many thanks for the awesome help I am sure you will give.

Bob

 

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I run all fans on a separate PSU, so I can control exactly what happens without relying on the printer to control it.

The steppers get very hot, and mine would reguarly be hot enough to be painful to touch (before direct drive).

I dont think there is any issue, and am 99% sure you only notice because the motors are now sticking out so you can touch them.

C.

 

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Deciding on heat sink placement

Took a bit to cut and grind the new longer rods. I also swapped over to slightly shorter (and now very tight w/o any additional tensioners) GT2 belts and pulleys.

If anything the new setup feels like it has more drag, but I'm sure it has more to do with the very tight new belts. They all sing about the same note.

I swapped the wire pairs on the motors as it only took a few seconds and I should never have to worry about customizing that bit of the firmware.

Just curious about placing the cooling fans; any reason not to mount them atop the stepper motors as pictured ? Alternatively,I was also thinking about placing them under the motors and adding a couple zip ties just to make sure the adhesive doesn't fail.

 

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The reason I put the fan on the back, is that the metal there is one nice big flat surface, but in the

middle its three things sandwiched...so not quite so good for the thermal conductivity. But honestly

on the top is probably completely fine.

I would be concerned if the tension is now so much that its harder to move than before !

If its that high, your bearings will be suffering alot and you are in danger of skipping steps (esp when the head

nozzle tip rubs across a bit of raised print).

I would recommend considering a new slider block arrangement like this one, which decouples the clamping

of the Ø6mm rods and the belt tensioning functions. So will probably make it easier to tune your belts a bit.

http://www.thingiverse.com/thing:45236

Looks nice though !

 

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I think you are correct, Lars. I follow this thread occasionally, because belts are a PITA--especially MXL belts that don't seem to be terribly available in the U.S.. I plan to throw away my short belts someday and install GT-2 pulleys and long belts for this reason. We are pushing viscous liquids around and, given reasonable expectations for the precision of this process, I think the performance of the X/Y drive system outshines the Z-stage stability, regardless of how we move the print head. I have a heated bed made from 5/16" Mic6 aluminum tooling plate (quite dimensionally stable with temperature changes) and I'd like to build the entire Z-stage, arms, and bearing mounts from Mic6 someday. I've improved the return to zero of the bed height adjusters too. I hate to reduce accessibility, but I agree that another Z axes rod in front is very compelling.

 

I think a third linear bearing at the front would do really well. I'd wager a lot of the "ringing" that people see, is in the bed, not the head.

 

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Here in the states Ultimachine sells the couplers and 8 mm steel rods. The steel rods were part of a 5 rod kit to make a 3d printer. All these parts worked well in the assembly to get rid of the short belts. Only needed to cut one of the steel rods. A dremel with a metal cutting disk did the job without any trouble.

Thanks for the information to make the upgrade Calum!

By the way Ultimachine sells 3mm plastic. So far it is the best I have used that ships within the states.

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Hi all,

I really want to install this upgrade but struggling to find a decent supplier of flexible couplers here in Europe (don't really want to wait 4-6 weeks for delivery from US).

I read that some of the earlier ones Calum ordered where crap so was hoping that someone might have a link to something tried and tested.

Thanks in advance!

 

 

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I have never recieved any crap ones....

The best ones I got from China (amusingly enough), I got some others from Germany which

were not quite as good (they were a bit stiff for my liking).

Just google 5mm to 8mm flexible coupler. Or try ebay, there are loads. Just make sure you

get ones with pinch clamp design, and not grub screws.

 

 

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My bad, sorry I misread your post in September where you referred to shafts which sucked(needed reordering) and you were expecting the couplers from China to be rubbish but they turned out ok.

Thanks for the info, I'll recheck around ebay a bit and try to find a local sender.

Cheers

 

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snowygrouch

Did you already redesigned the Mooncactus blocks? I am be of the mind that I read in another topic that you are thinking about it because the problem with deformed bush bearings.

 

Lars86

Please correct me if I'm wrong - I struggle a bit with my school english. Did I understood right that an more heavy Z stage is better than a light one? In my opinion that makes sense because an (heavy) inert mass transferred less oscillations. But on the other hand I used a 5mm milled aluminium plate with a heated pcb on it and a 4mm oven glass on top. Thats definitly a bit more than one additional kilogram. I observed that the original wooden stage is on its load limit with that. At least at the foremost springs. A more stable stage construct or a third shaft seems a very good idea.

 

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snowygrouch

Did you already redesigned the Mooncactus blocks? I am be of the mind that I read in another topic that you are thinking about it because the problem with deformed bush bearings.

 

Lars86

Please correct me if I'm wrong - I struggle a bit with my school english. Did I understood right that an more heavy Z stage is better than a light one? In my opinion that makes sense because an (heavy) inert mass transferred less oscillations. But on the other hand I used a 5mm milled aluminium plate with a heated pcb on it and a 4mm oven glass on top. Thats definitly a bit more than one additional kilogram. I observed that the original wooden stage is on its load limit with that. At least at the foremost springs. A more stable stage construct or a third shaft seems a very good idea.

 

Yup, you got it. Heavier is better for the z-stage. It helps take out the lash in the bearings, and to dampen out vibrations.

Stiffer springs are an easy solution to your problem.

 

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Rather it is the fact that the 5 mm wood board is pressed down unequally by the springs at the front edges because the last 40 mm at the front are not supported by the side arms. Its possible for me to balance it with the springs but I have the (in this case) negative flexibility of the birch wood in mind. :)

But this is a topic for itself.

 

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