X-Motor Mount One Piece Print Idea

While looking at what other wooden parts on the printer I might be able to make in plastic, I started working on a plastic replacement for the X-Motor mount. I initially designed it just like the original in 2 parts, then started looking at making this into 1 part which would cut out 4 bolts & nuts. Since I would have to print this on its edge, I added some ears to the bottom to give it a larger footprint. Looks like I could also add some extra width to the front bottom of the part if it needs a bigger footprint for printing. There might be an overhang problem with the top circular cut above motor, but I could bring in those 2 horizontal openings a few millimeters. All the bolt holes would be horizontally printed, but I have had pretty good luck with horizontal holes lining up although they are usually not as round as vertical holes. Print estimate is about 4.5 hours at .2 infill, so it will probably take 5 to 6 hours to print. I would be interested in any thoughts on this before printing it. I cut the corners to 45 deg. chamfers & some extra holes to save a little plastic. Attached are three images of what it should look like. On the 2d image, the holes are Red, Outline in Green, Motor in both extended positions is in cyan & alum. is white.Attachment 6087Attachment 6088Attachment 6090

Why does it need to be printed on edge? I would think it'd be stronger printed flat, with a few supports.

I was initially looking at doing it that way, but did not like the idea of supports. I was going to use a grid of cones in each quadrant of the motor mount holes, starting with 2 to 3mm dia. at base & 1 to 2mm where it touches the top. Maybe I will try a test print of just a quadrant 1st to see how it looks. I got side tracked on another idea of placing my raspberry Pi with the LCD panel, so will get back to the X-Motor after I work on this. Thanks for the suggestion.

Is the spacing on the holes the same, so that one can use the holes in the frame to access the screw heads?

That is a very good point. I used my flatbed scanner to scan all my wood parts when I first bought this & was using that as the guide for the hole patterns & sizes. I just checked it & they match. I also used a dxf file of the i3v 12" scan file that beerdart uploaded to this thread to check to see if this is the same for the 12" & it seems to be. http://3dprintboard.com/showthread.p...ighlight=plate I knew scanning all those wood pieces in would come in handy one day. Thanks for the thought. I could very well have missed that problem before printing it. I am starting to lean towards printing this flat with support as AbuMaia suggested.

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Originally Posted by PyramidDave

I would be interested in any thoughts on this before printing it.

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Assuming printing on the flat side instead of vertically, and printing this as one piece rather than two, one suggestion would be to extend some reinforcement edges at the top and bottom to the right from the doubled-up part. A weak point in the wood design is at a vertical line between the doubled-up part and the horizontal v-rails. The large plate won't flex behind either the motor or the v-rails, but belt tension can cause the large plate to flex at that weak point line; your design carries forward that concern. Extending some reinforcement lips or ridges forward at the height of the doubled-up part might help reduce flex there. On the bad side, those reinforcements would have to work around the upper idler wheel bolt head and Z-nut bracket, and many of us have relocated the X-endstop to the bottom of the lower v-rail. Perhaps the reinforcements don't have to overlap the v-rails very far for them to be of benefit. Another thought is that the reinforcement might be achieved by adding it in the area between the two v-rails rather than at the top and bottom.

That sounds like a good idea. I had not thought about the belt pulling on that part. It would be quite easy to add a ledge at the top, bottom & Left side of the plate, kind of like I did the ledge on my 2 part Y-Bed design. I used an eight sided polygon extruded along a path for that, centered on the top edge of the plate. I will take another look at this in a day or so.

While the ideas were fresh in my mind, I took a look at this again tonight using printbus suggestions as I understood them. I used a thickness of 6mm for each of the plates. That seems to match the thickness of the wood pieces. Here is what I came up with so far. I attached an image & a stl file for you to take a look at. I think the hole patterns should be pretty close, but the square hole might be a little over size. I do not plan to use the square hole, but a part from thingiverse that I remixed.Attachment 6120Attachment 6121

Attachment 6125I found one small problem where the weld along the inside vertical was showing up underneath & I trimmed the arcs above & below the motor mount so they did not extend outside the cutout underneath. Here is the newer stl file & image to show what it looks like.Attachment 6124

Attachment 6126 Here is one last revision. I made the front plate a little smaller, added 2mm to the outside edge of it & added a larger weld to the inside vertical side of that.

Attachment 6130 I played with this design a little further & kind of like this shape. It has a little more character than just a simple rectangle shape. Attachment 6129

I did my 1st test print of this part last night. I printed at 60% infill with PTEG on a BuildTak surface. The shorter corners on the Motor end both lifted up a little, so I was going to add some ears, but then decided to try adding some extra curves to break up the long lines. I will add the ears if it still lifts up this time. I believe it was clough42 that mentioned breaking up the long lines in a post on this newsgroup somewhere helps it from lifting. Other than the lifting up, the test print came out pretty good. The wheels line up well when I put them on a spare 20x20 extrusion. I increased the height of outside Ledges by 1mm, the height of the center weld to match the top of the plate, added a small fillet weld on the inside vertical where the motor mounts & extended the top plate .5mm to the right. That top plate was barely going beyond that motor cutout, but that big top vertical fillet weld should take care of most of that weakness. Here are 2 photos of the test part & an image of what my latest derivation looks like. If this test print goes well, I will test fit it on the machine. I added holes on the outside 4 corners also as it seems like that will give it some more strength & also might come in handy for putting something there.
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I am really liking how you are rebuilding the i3V and making it printable :-) i can't wait to see what you come up with for the main frame and if you can actually make it stronger than the wood :-)

Thanks. It is kind of fun and is helping me to understand what I can & can't get to work. I am also working on the LCD holder & making that a 1 or 3 part print. My thought on the LCD bracket is it might be a better place to mount my raspberry pi behind the LCD panel.

I think this is the final print. I had to add some ears as the curves did not eliminate my lifting problem, but the ears did. This part feels quite strong. I initially tried creating my own support system using draftsight for the 2d & turbocad for the linear extrusion along a path, but the sli3r support system seemed to work better. Since I did not have a spare motor, I printed a plastic representation of the part of it I needed to test for fit. I initially used needle nose pliers to pull most of the support out, then used a chisel & x-acto knife carving set to clean the last part of the back flat. I was not crazy about having to clean up the supports & does not look real pretty in the back, but the test motor part fits well. The weight of the plastic part with 60% infill of PTEG is 1.78oz. Here are 3 photos of the part.Attachment 6148Attachment 6149Attachment 6150

Just as soon as I thought I had it right, I missed checking the T-nuts. Easy enough to fix on the model, but wish I had seen that before printing it. Glad I had some extra extrusions laying around so I could see this before taking the printer apart.Attachment 6151

I checked the clearance of the T-nuts & this seems like it will work. Will print it again tonight or tomorrow to see if it works. I added another weld around the plate at the bottom & top since the plate does not really overlap the hole on the inside vertical. I am printing the X-idler plate now.
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Thought I was going to be taking my printer apart to replace the X-Motor Plate & X-Idler plate today. I think the X-Motor Plate really needs 4 wheels instead of 3 as the plastic flexes some between that middle wheel & upper & lower corner. I had the extra holes for mounting it, but did not countersink for the eccentric wheel. They were also off by 1mm from the other center eccentric hole. I may as well get this right before taking my printer apart. I was able to create my own support system instead of using sli3r's method. It seemed easier to clean up. I used like an upside down "V" profile for the plastic overhang support where the motor goes. I was able to get most of the plastic out by prying this way & that with a pair of needle nose pliers. I also used a file, small wire cutters & then a dremel type tool for smoothing the surface. When putting this together, I noticed the T-nuts show by 1mm beyond the aluminum. I will move those 2 holes another 1mm to the right before printing.

Weight for this part at .6 infill of PTEG is 1.75oz & the time to print it was 02:34:05Attachment 6167Attachment 6168Attachment 6169Attachment 6170Attachment 6171

The test fit on some spare v-slot fits pretty good, so I went ahead & published this on thingiverse today: http://www.thingiverse.com/thing:853811

It might be a week before I can change this on my printer as I just ordered some wheels to change. I will probably publish the X-idler plate tomorrow.

After some further looking at this, not sure it does really need 4 wheels which brought up another idea for a design change. Since only 3 wheels are used, there is really no need for the plastic going all the way to the corners that I can see. Plastic volume is 3.6 less cubic centimeters (44.9 instead of48.5). I also fixed my support system for underneath. It was a little too close to center side.
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This looks great. What program you use to 3d model.

I create the 2d profiles in Draftsight which is free AutoCAD clone (I wish it had lisp capability though). I would prefer to use AutoCAD, but do not have a license for that. I wrote a visual basic program to create the Linear extrude data rather than importing a dxf file into openscad. I just do a list of the polyline data & copy & paste that into the visual basic program. I use turbocad to generate the ledges by extruding along a path as that was the simplest way for me to do that. I probably should spend some time learning more of the features of turbocad as it seems quite powerful for the money. I also use turbocad to generate DWG files from STL files to use in Draftsight.