[extreme]

Hello everybody,
I'm starting on a router/milling machine and would like to hear some tips from you. I learned Solidworks and designed the machine here first.
It will be used on different materials, but mostly aluminium.
Router will be made of 20mm and 15 mm aluminium plates, Chinese 20 mm(x,y) and 16 mm (for z axis) supported rails, Chinese 16mm/5mm pitch ballscrews.
Probably I will use 1.5kw or 2.2kw, again, Chinese spindle and 300 oz/in motors.
Rail size is 750 mm 600mm and 300mm for Z axis.
Rails, screws, motors and controllers are already ordered.

Please check the attached pictures and see if you can find any flaws before i begin. All feedback is welcome.

[Dylwad]

Looks good, only thing you might consider changing is move the z rails to the spindle mounting plate, and the blocks to the x carriage. Should end up with less material and a stiffer z assembly.

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[ger21]

Use 10 or 20mm pitch ballscrews. 5mm screws will be very slow.

[fuper]

Hi Extreme -

Looks good. I built a similar device and just finished it recently. I like the supported rails approach. I used end supports only and there is a bit of give in the middle when cutting. Not too bad if I move things slow but it's there. I would suggest using mic-6 plate for the base plate [or similar]. It's ground flat, not terribly more expensive than aluminum and is more temperature stable than regular aluminum.

I'm not sure what the back brace is for on the X axis? Stiffness? With the supported rails on top of the aluminum back plate should be sturdy enough. I always felt the corner joints could be beefed up but I never did anything with mine.

Shane

[extreme]

Hello guys, thanks for input.
The idea of changing z axis seems good. I redrew the axis. I will consider that, or some stiffening on the spindle plate. It also seems the same amount of material.

About the screws, they are already ordered, so at least for now i will stick with 5mm pitch.

Shane, do you have some pictures of your machine ? I agree it would be nice to have a precise table plate, but I have materials already at work and I think those plates might be not available in my area.
That brace was the last thing I added, not sure if I will use it, probably will decide when I start to build the x.


Attachment 188878Attachment 188880

[Dylwad]

Hello guys, thanks for input.
The idea of changing z axis seems good. I redrew the axis. I will consider that, or some stiffening on the spindle plate. It also seems the same amount of material.

About the screws, they are already ordered, so at least for now i will stick with 5mm pitch.

Shane, do you have some pictures of your machine ? I agree it would be nice to have a precise table plate, but I have materials already at work and I think those plates might be not available in my area.
That brace was the last thing I added, not sure if I will use it, probably will decide when I start to build the x.


Attachment 188878Attachment 188880

Looks good, but you can lower the bearing blocks a few inches now, or at least the lower ones so they are spread out more, and the lower ones can be aligned with the bottom of the carriage.

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[fuper]

Hi Extreme -

http://www.cnczone.com/forums/open_s...en_source.html

There are a bunch of pictures as well as on fuper.com

Your's is a more elegant design I think than mine. I also never built anything before I put mine together!

I hear you about having the materials on hand already, might as well use them.

Also - have you given any thought about how you are going to mount your material for machining? I ended up laying out a grid of holes on a 1" grid tapped for #10-32. All told I think I did something like 11^2 holes. Took forever but I finally finished.

On a second go I would switch to a t-slot. The holes get filled with crud and are a pain to keep clear. I don't have a good supply of air to clean things out as my compressor is really noisy and I live in an apartment and most of my machining is done at night after work, you get the idea.

Shane

[extreme]

Hey fuper, your web seems to be down. Your machine looks great, considering it is your first build. Next one will be much better. Some years ago I tried to make a router the parts I had on hand, it was a failure

Not sure about material mounting method, but was thinking about drilling holes, taping or using some kind of inserts like this POPNut Steel Open End Linear Knurls Threaded Inserts - Stanley® Engineered Fastening . Would be nice to just drill the holes withe the spindle and just press inserts from the other side. Also if you happen to damage the thread, you just pop a new one there.
Looking forward to receiving the parts and starting on the machine.

[fuper]

Thanks Extreme - I just renewed the domain. Hehe totally forgot thanks for the heads up. It should be back up in a few hours. Also thanks for the kind words about my build. It does work and after I tightened everything up it keeps reasonable tolerances for something home made. I learned tons. Right now I'm working on a CNC lathe build, will hopefully document more on that soon.

I've seen inserts like the ones you linked too. I've also seen ones with cams, basically off-center circles that lock the device in place against pins like the ones you showed. Those are interesting, don't have a link handy but they are common for tooling plates. I don't have the means to mill out a t-slot easily otherwise I would just do that.

What are you going to control it with? I went with a Gecko G540 - really happy with it, and for $299 [US] I think it's a bargain, good company too, they repaired my device for free when I used shotty stepper motor cables that melted [not rated for 3 amps].

Keep posting on your build.

[extreme]

I will be using drivers from china, basically I will have a Chinese machine Here is the link Stepper motor driver DM542A, 4.2A, 18-50VDC, CNC New | eBay
I will update when I start the build.

[extreme]

Dylwad, there is a problem associated with that. If I lower the blocks, I loose the same amount of travel. To regain the z travel i would need to rise the gantry. I'm kinda leaning towards the original idea + adding some bracing.

[extreme]

Got electronics the other day from longs motor. It was packed very well. Everything seems pretty good quality, i even opened the controller to have a look and it looks good. Connected everything together on bench, and it works!
I'm using a laptop and a express card adapter, seems to work. If later I get problems with signals, i might get a smooth stepper or similar.
Should receive rails/screws in a week or so.

[wizard]

The forums software screwed me up but here is what I wanted to say:

I will start with the Z axis as that throws up red flags right away especially if you are looking at a > 1KW spindle. In a nutshell the spindle needs a lot more support than one thing clamp at the spindle nose. Combined with the spindle sizes you have mentioned this set off alarms right away. Think about it, even guys running motor tools and compact routers out more effort into spindle support than this design has.

Some one already mentioned flipping the Z axis rails and cars. This is good advice.

Beyond that, I'm concerned about the stiffness of various panels you are employing. However there is little said about your intended usage, so I'm not certain it will be a big problem. I'm also not clear on assembly, are the vertical supports for the Y weldments. I just see a design here that looks like it was put together without a thought to how real world fasting will happen. I can't really say the design is bad or good because intended usage is a factor but generally you want a rigid machine to make the best use of a large spindle. Little things like hoe the parts are held together can impact viability of the machine.

[extreme]

Hey wizard, thanks for comment.
I'm looking at 1.5-2.2 kw spindle. When I look at it again, it really looks a flimsy. Do you think it is better to reverse the rails/trucks and make the tower 40mm higher, or leave as it and add some bracing ? I added one more clamp on top of the spindle, do you think that is sufficient? I also drew a beefier version, please comment.
Attachment 190494


Attachment 190498

As for assembly, I plan to bolt everything together. Although I weld aluminium for living, i think it will warp too much, and i do not have the possibility to machine the parts after welding.
I am also going to add some kind of a frame under the table. I might weld that, and bolt it after.

I would like to have the machine stiff, so I can mill aluminium. It is still a hobby use, but if I can make it better, I will.

Wizard, it seems that you have experience in this area, so please advise how improve my router, maybe some specific suggestions?

Thanks again for input.

[wizard]

Hey wizard, thanks for comment.
I'm looking at 1.5-2.2 kw spindle. When I look at it again, it really looks a flimsy. Do you think it is better to reverse the rails/trucks and make the tower 40mm higher, or leave as it and add some bracing ?

I think you want to rethink this design carefully. For example the lower bearings on the Y saddle should be as low as possible.

I added one more clamp on top of the spindle, do you think that is sufficient? I also drew a beefier version, please comment.

If you want to machine aluminum I'd go with the beefier design. If the robust unit is a problem the two clamp method will work. For the two clamp method I'd make the lower clamp out of thicker material.

As for assembly, I plan to bolt everything together.

Bolting isn't a problem if you have a design that works well as a bolted up structure. I'm not sure the vertical parts qualify as a good design for a bolted up structure though. You need a way to stiffen those vertical columns.

Although I weld aluminium for living, i think it will warp too much, and i do not have the possibility to machine the parts after welding.
I am also going to add some kind of a frame under the table. I might weld that, and bolt it after.

A welded up structure would have advantages, but you are right you need to get the parts machined afterward and maybe even stress relieved before that. On thing to consider is what welding does for the aluminum, generally it weakens the aluminum significantly. Given that I'd seriously consider a weldment even if you have to pay somebody to machine the parts square afterwards. This especially the case if you can weld to a professional level. Yeah it will cost some bucks but it will give you nicer results you can leverage your skills as a welder and then benefit do from somebody else's skills. I'm assuming here that as a welder you have contacts in the machining world.

Given the above if you intend to weld things up, such as the vertical supports you need to add gussets so that the columns can resist vibration and flex in both directions. Or skip welding altogether and go with much thicker material for the verticals.

The thing is this if your primary material is aluminum, to get good results you need a stiffer machine than what would be acceptable for CNC machining wood, circuit boards and the like. Combine that with the spindle size you want to run and I would suggest carefully thinking about the stiffness of the entire machine.

I would like to have the machine stiff, so I can mill aluminium. It is still a hobby use, but if I can make it better, I will.

Well you need to fit device into your budget. It really depends upon how much aluminum you intend to machine, how much time you want to take doing the machining and the quality you expect.

Wizard, it seems that you have experience in this area, so please advise how improve my router, maybe some specific suggestions?

Routers not yet, I spend most of my days working on machinery making precision parts though. The thing that caught my eye and caused the greatest concern was the Z axis and the spindle mount. You need to stiffen up the rest of the machine if you want to use all the power of that spindle.

Thanks again for input.

No problem, looks like you are off to a good start.

[extreme]

Thanks for the reply.
Have been looking for new ideas and drawing last two evenings. It's starts to get complicated to figure out how to make it work, but I came up with something.
Machine starts to look robust, the gantry at least.
I'm thinking of basing gantry on a 100x100 mm square tube with 12.5 mm wall rather than 20 mm aluminium plate. I might weld in two 15 mm plates inside the pipe for bolting it to side panels. Changed the position of the rails and the carriage. I also changed side panels from 15 mm to 20 mm and added gussets, I may add one more set of gussets. It still will be bolted.
I have not figured out where to put the ballscrew for y axis yet. I would like to put the nut inside the Y carriage, but then it will hit ballscrew supports. I'm thinking of either removing a small part of carriage to clear the supports or to mount the screw in the back. It was so simple with the old design.

I would weld the parts, but will try to avoid it. Machining will cost as much as the rest of the project. In Norway (I'm living in Norway currently) a machining workshop will ask at least 150 $ per hour, and nobody is in a hurry. That is out of the question, unless some small parts.

I need to rest my head now, maybe I will come up with something better later.
Please comment on my new ideas, i attach some pictures.


Attachment 190810 Attachment 190812

[wizard]

Thanks for the reply.
Have been looking for new ideas and drawing last two evenings. It's starts to get complicated to figure out how to make it work, but I came up with something.
Machine starts to look robust, the gantry at least.
I'm thinking of basing gantry on a 100x100 mm square tube with 12.5 mm wall rather than 20 mm aluminium plate. I might weld in two 15 mm plates inside the pipe for bolting it to side panels. Changed the position of the rails and the carriage. I also changed side panels from 15 mm to 20 mm and added gussets, I may add one more set of gussets. It still will be bolted.
I have not figured out where to put the ballscrew for y axis yet. I would like to put the nut inside the Y carriage, but then it will hit ballscrew supports. I'm thinking of either removing a small part of carriage to clear the supports or to mount the screw in the back. It was so simple with the old design.

I'm sure you can work these issues out.

I would weld the parts, but will try to avoid it.

Welding is up to you but even if you don't weld you will still need some fairly precise machining on some of the parts. That is fairly easy to do on aluminum in a limited shop but is lots of work if you go to steel. In the end if you don't order custom cut extrusions you will need to machine many of the parts anyways. Welding up some of the structure and then machining afterwards might actually save you money.

For example you have two columns to support the Y axis. If you do these out of plate you still need to machine them square or parallel as needed. I don't see a way to get around this in a custom machine. In the US you can order extrusions cut and machined as needed which make it far easier to put a machine together, I'm not sure how easy that would be to do in Norway. The reality is though that you still pay for that machining.

Machining will cost as much as the rest of the project. In Norway (I'm living in Norway currently) a machining workshop will ask at least 150 $ per hour, and nobody is in a hurry. That is out of the question, unless some small parts.

Think about this carefully! You still have to get some machining done for all of those plates. It may be cheaper to put together a roughly machined weldment and then have in machined afterwards. With a weldment you may only need to flatten a surface and square it to another or make it parallel as needed.

$150 an hour may sound like a lot but do consider what you are trying to build here. You are basically building a milling machine to handle machining aluminum. Obviously you want to minimize machining as much as possible. Beyond that if you focus on machining the critical parts with a machine shop you can use the machine to mill the rest of the parts.

I need to rest my head now, maybe I will come up with something better later.
Please comment on my new ideas, i attach some pictures.

I don't especially like the rails on the top an bottom of the Y axis beam. Any imperfections in the beam will result in binding. This can be dealt with by machining the beam or hand scraping the surfaces parallel. You could also try shimming the rails. Still I think you are asking for trouble with this sort of design. I'd keep the rails mounted on one plane. This simplifies things considerably.

[extreme]

I hope I'm getting somewhere. I went back to a earlier design due to I can't find a good way to mount the ballscrew assy for y. Anyway, I think I like how it looks now. Some key changes :
changed the shape of the gantry legs
added two braces to gantry backside ( extruded 15x60 solid rod)
changed the plate one the y carriage to a two plate sandwich. This gives me the best compromise ( i hope) between gantry height, z travel and distance between the trucks and rails. Also, otherwise i have no way to attach the trucks on the same point on both sides.

Some pictures for revision.



Rails and screws should be here on Tuesday, pretty keen to start the project.

Solidworks begins to be quite usual This router is my first drawing.




Attachment 191080 Attachment 191082 Attachment 191084

[CaptainVee]

I'd turn the gantry around so the motors for x are on the other side, and probably add a torsion box for a bed. But it looks very promising, especially since you are listening to all the advice!

[extreme]

I'd turn the gantry around so the motors for x are on the other side, and probably add a torsion box for a bed. But it looks very promising, especially since you are listening to all the advice!

Will do sir I was planing to do so, just a little tired of sketching.