Work scrap bin router build

[Vic66]

According to Hepco, The dual V bearings I have (W3) are 5900N raidal and 1701N axial, literature here... http://www.hepcomotion.com/en/view-pg-21-view-6

I aquired 12 of them from work for nuppence they were left over from a job, and based their use on Joe's Hybrid design here... http://www.joescnc.com/themachines-hybrid.php

I was a bit skeptical about running them on steel angle rather than the ground V they are intended for but Joe seems to have had success with his design.

I originaly went for box, attached pics of the unfinshed box section model below, I could return to box section, I've been thinking about what Irving said in a previous post about cutting access holes for spanners etc, this would mean re thinking the position of the lead screw on the X axis though, which could make the X axis carridge more complicated.

I would rather not buy any supported rail, financially I have to run with what I have but I take on board the comments made about the side load on the bearings.

With the forces Irving calculated would this be an issue though ?

Vic

[irving2008]

I see Vic, hadn't looked that closely. How thick is your steel angle and are you planning to prepare the edge in any way? The side load will translate into a vertical and horizontal force due to the shape of the vbearing. If they are rated for 1700N axially then I would have thought that was fine - I suspect the bearings would force the rails towards each other (or the studs apart) and pop-off the rails long before the bearing gave up!

[Vic66]

Apart from cleaning them up I wasn't planning on preparing the edges, they havent in Joe's design, the V is running on the natural small radius of the edge of the steel angle, the V bearings can be run inside an angle which seems a better way but I could'nt think of a simple way to mount an angle in a suitable attitude.

Angle I've shown is 25mm x 3mm I would rather use 4mm or 5mm 20mm angle but that isnt a size that we stock at work.

[Ross77]

Hi Vic
FEA looks good, I need that program.....looks so much quicker, dose it also generate a list for validating? How does it calculate the fixing type at the bearings or is it asuming a rigid connection?

From the analysis it looks like the z axis plate is the weakest as its only a 2d plate. Id mount some angle on it parallel to the spindle for strength.

For the C channels on the long axis you could flip them 180 deg so the web is on the out side and directly below the angle also it might be worth getting some unequal angle for the vee bearings, something with only 10 or 15mm upstand would be much better. Alternatley you could stick with the original config but add a plate to close the channel, this could extend up and bolt in to the angle as well to help brace them, two birds one stone etc.

This would also be a good idea for the x axis (?) as the open C channel is weak in torsion, need to move the ballscrew tho. As a final observation the vee bearings are only bolted to the end plates, it might be worth incorporating their mounts with the C channel uprights.

Anyway good luck.

[Vic66]

To be honest I'm not that experienced with the stress analysis side of the software, I design specialist vehicles, mainly steel framework, sheet metal with some mechanical elements to it www.jsfraser.com all the CAD stuff on the site is mine. We've only had the version of the software with FEA for a year now and so far I've just used it for testing framework bending over distance and seeing what sort of lightening holes I can get away with, so I'm not really qualified to answer your question, I have the disks though which will install as a 30 day trial version, you want a fairly decent PC though.

I keep having different ideas for my router, I settle on one idea get it modeled then think of something else, I've got to draw a line soon and go with what I've got or it's never going to get built ;-)

I know what you mean about the z axis plate, one of the other designs had angle along the side, this one has two 16mm supported rails bolted to the back of it, I bought them from a member on here, the bend on it is extremely slight, it's not to clear from the still pictures but when you can spin the model round you get a much better idea of what is bending and what isnt, its mostly the channel deflecting, I'm thinking about going back to box for this.

I've also thought about using steel box for the long axis, with 25mm angle tacked top and bottom with the ends of the angle laid on the box so it looks like a pyramid when viewed from the end, this would give the V bearings much more contact area and the angle is less likely to deflect, I've been trying to avoid welding because of distortion though.

[Ross77]

I keep having different ideas for my router, I settle on one idea get it modeled then think of something else, I've got to draw a line soon and go with what I've got or it's never going to get built ;-)

Unfortunatly the best way to find out if it works is to just build it. if its only your time then I guess it dosnt matter and is part of the fun eh.

I've had a quick look at the hepco site and those bearings should be fine as when used in opposing pairs the double vee forms a 4 way equal loading. not sure about relying on the load capabilities if using the rounded edge of the angle as a rail tho. as the contact area is reduced to only 2 or 3 points.

I've also thought about using steel box for the long axis, with 25mm angle tacked top and bottom with the ends of the angle laid on the box so it looks like a pyramid when viewed from the end, this would give the V bearings much more contact area and the angle is less likely to deflect, I've been trying to avoid welding because of distortion though.

Using the corner of the angle would be better from a load point of veiw but I feel you may have problems aligning them, the reduced contact of the rounded angle maybe more forgiving. (test if you can).

An easier option IMHO is to use a rectangular box and rotate it, as the pic, No bolting requred and both corners will be parrallel, there is also space for the ballscrew. The box section is better at resisting the torsion from the z and y axis's.

I still think that just adding some closing plates to your original idea is the best. its still modular as you wanted and the smaller contact from the edge of the angle should make alignment and adjustment easier

I have the disks though which will install as a 30 day trial version, you want a fairly decent PC though.

Are you offering to loan them to me? I could probaly get most of what I want to do done in 30 days, Ive got a dell precision 470, 6.4 Ghz 3mb memory and nvidia quaddro 540 (I think) will that do?

[Vic66]

Thanks for taking the time to do the drawing, the closing plate idea was going to be my strengthening measure if the channel flexed to much. Using box section as a rail but rotated had occured to me, but I was put off by the radious on the corner of steel box section, Ally has a nice square corner but wouldnt last long with the bearing running on it, I'll try running a bearing along the edge of some steel box and see how the V matches the radius.

[Wobblybootie]

It may not be much use but Pacific Bearings have a 'square' bearing using hi tech plastic as the bearing surfaces, each side can be adjusted for clearance .. but I think these may have to run on steel box section ...

[Ross77]

Thanks for taking the time to do the drawing, the closing plate idea was going to be my strengthening measure if the channel flexed to much. Using box section as a rail but rotated had occured to me, but I was put off by the radious on the corner of steel box section, Ally has a nice square corner but wouldnt last long with the bearing running on it, I'll try running a bearing along the edge of some steel box and see how the V matches the radius.

No probs with the drawing, probably took me less time than trying to explain in words.

Well at least you should have have enough options now.......looking forward to seeing some pic's

It may not be much use but Pacific Bearings have a 'square' bearing using hi tech plastic as the bearing surfaces, each side can be adjusted for clearance .. but I think these may have to run on steel box section ...

Not sure I would bother personally, looks like theres alot of surface contact so high friction and being fully enclosed means the rail cant be supported. I would also guess that the rail would have to be solid as box sections often have slightly concave faces.

Still i'm sure someone will prove me wrong :heehee:

[Vic66]

Still pondering at the moment

Just out of interest I've attached the model in DWF format, you'll need Autodesk design review to view it, tiz free

http://usa.autodesk.com/adsk/servlet...&siteID=123112

Still got some fettling to do