Router Build Mk 1

[Clive S]

Its always nice to see a new build log, keep it going and don't be afraid to ask questions. Good luck with the build.

[routercnc]

Nice work hoppo. Any pictures or sketches of the whole design?

[Desertboy]

KJN are excellent, I live right next to them and they have been invaluable to me ;)


Good look with the build

[hoppo]

Here are some rendered drawings of my design. Some bits are missing like the motor and pulleys on the second X axis ball screw but they are identical to the other side only mirrored so you should get the idea.


Overall view.



Front view.



Side view.

The hardest part of anything so far was learning the CAD software to ensure my design would work. I've been using Autodesk Fusion 360. Which is very good but I haven't really got anything to reference that against. There may well be better software out there, but Fusion 360 is free and seems to have done the job even if it runs a bit slow on my computer. Apologies for the state of the pictures in this post, they don't really show the construction too well.

[Desertboy]

Hi,
Good luck with your build, I'm no expert but looking at your cad models 2 things springs to mind.


I am going to do things differently to you and not have the 4 corner plates, instead I'm going to bolt the supported rail to the sides of the extrusion and the ballscrew to the top and have vertical plate mounts.
Of course the disadvantage of mine is it's direct drive via couplings.

A little late now but KJN offer a drilling service as well so you can do away with the corners and bolt through the extrusion I'm going to have mine drilled AND use the corners.

[A_Camera]

Of course the disadvantage of mine is it's direct drive via couplings.

That's not just disadvantage... it can be an advantage as well since you won't have issues with backlash. The way I see it is that the only disadvantage direct drive has is the maximum speed limitation. On the other hand, it is giving very good torque and the best possible accuracy.

[hoppo]

Hi,
Good luck with your build, I'm no expert but looking at your cad models 2 things springs to mind.

I am going to do things differently to you and not have the 4 corner plates, instead I'm going to bolt the supported rail to the sides of the extrusion and the ballscrew to the top and have vertical plate mounts.
Of course the disadvantage of mine is it's direct drive via couplings.

A little late now but KJN offer a drilling service as well so you can do away with the corners and bolt through the extrusion I'm going to have mine drilled AND use the corners.

Hi Desertboy,

Thanks for the comments. I did think about placing the supported rails on the side of the extrusion. The one reason that I didn't was because of the tolerances of the cutting of the aluminium profile for the Y axis. KJN quote, I think a tolerance of 0 to +2 mm. Which I thought if this was the worst case and was 2 mm over I would need to use shims. Whereas bolting to the top of the extrusion gives me a certain amount of wiggle room with the bolts in the slots to remove this tolerance if required. I'm not sure if that is best practice, it just seemed to make sense at the time I ordered the profile.

I did also consider direct driving the ballscrews. In hindsight the best thing I could have done is got 1610 instead of 1605 ballscrews and then I would have had speed as well as torque by direct driving them, but at the time of designing I think I was more interested in the speed and hadn't really considered the potential backlash issues. I could I suppose easily convert to direct drive later if backlash becomes an issue.

Cheers

[Desertboy]

Hi Desertboy,

Thanks for the comments. I did think about placing the supported rails on the side of the extrusion. The one reason that I didn't was because of the tolerances of the cutting of the aluminium profile for the Y axis. KJN quote, I think a tolerance of 0 to +2 mm. Which I thought if this was the worst case and was 2 mm over I would need to use shims. Whereas bolting to the top of the extrusion gives me a certain amount of wiggle room with the bolts in the slots to remove this tolerance if required. I'm not sure if that is best practice, it just seemed to make sense at the time I ordered the profile.

I did also consider direct driving the ballscrews. In hindsight the best thing I could have done is got 1610 instead of 1605 ballscrews and then I would have had speed as well as torque by direct driving them, but at the time of designing I think I was more interested in the speed and hadn't really considered the potential backlash issues. I could I suppose easily convert to direct drive later if backlash becomes an issue.

Cheers

Hi I'm waiting for my ballscrews to arrive from China they will come tomorrow hopefully they are in the UK been tracking them ;)

like you I should have bought 1610 at least I bought 2 1604 1m and 1 1605 1.4m

I've reversed conventional design with my short and long axis because I have 25mm supported rail fror the short axis and 15mm hiwin for the long one.


I will hammer a lot more down when the ballscrews come but I was intending to just build it and only cad out the bits I need to.

I have a few choices for a base that's why I haven't worried too much at moment I thought get the axis moving first.

[hoppo]

Started construction of the Z axis front and rear plates. Armed with a hammer a center punch, a set of hss drill bits and a few counterbore bits off ebay and my trusty Clarke Bench drill this is the outcome.


Holes all marked out on the Z axis rear panel. This is the part that will attach to two ball screws and 8 bearings.


Drilling starts with earnest. Amazingly way easier than I thought it would be. I did use some cutting oil just in case and got a very good finish on the holes. Again as a newbie and not being too sure about my layout being particularly accurate I oversized the holes by 0.5mm to give me a little bit of wiggle room in case of alignment issues due to my possible dodgy setting out.


Finished drilling the holes on this plate. The larger holes are to take 10mm bolts to fit to the ballscrew block. Drilled at 11mm diameter.


The process begins again for the front plate that will hold the ball screw bearing blocks, spindle mounts and the supported rails.


More drilling.


The two plates with all the holes drilled. All look to be in the right place. I'm fairly happy with how fairly straightforward this was. It was working with aluminum that was most unsure about as I have no real experience working with it. It's just like drilling wood but smoother!


Countersinking of the holes to take the captive bolts that will hold the whole thing together.


The two finished plates, with all the holes in the right place and more importantly all the conterbores on the correct sides. There was a moment of panic when I thought I'd countersunk the larger holes on the wrong side but was relieved when checking the drawings that all was in fact correct. I did get some quite serious chatter whilst countersinking the larger holes. These are 18mm from memory and I had the bench drill on the slowest speed which is about 500rpm. I reckon it would have been better if it could have been slowed down a bit more. Anyway with plenty of cutting oil and only a little ringing in my ears afterwards I think I got away with it.

I hope I didn't 'bore' you all to death with a post that mainly 'revolves' around drilling holes. My wife thinks I'm mental having spent a day in the cellar doing nothing but drilling. Personally I loved it and am feeling quite chuffed.

I hope you found this post useful.

Cheers.

[Neale]

I could I suppose easily convert to direct drive later if backlash becomes an issue.

There are plenty of us using belt drive without backlash issues. Properly set up amd with the proper belt/pulley combination, backlash isn't a problem with belts. I use two drive motors for the master and slave X axis ballscrews on my router with short belts but there are quite a few builders who have gone for one motor with a long belt which works fine. I think that you should make the direct/belt drive choice based on other factors. I went belt drive as it meant that my motors are tucked in inside the overall build envelope, I can change drive ratios if I need to, and I get a bit of isolation of motor stepping from the ballscrew. It's also easier to build and adjust mechanically. Direct drive means very careful alignment (even if you are using Oldham/Lovejoy/flexible couplings). Both are viable methods but be aware of all the trade-offs before deciding.