Well here goes... Aluminium frame router design

[CharlieRam]

Well....
Ive changed my mind again! not sure whether to start another thread now.
I have decided that I am going to buy a mini milling machine for machining steels and simple plates ect which will help me build my router which will therefor be used mainly for woods and plastics with maybe the occasional bit of aluminium if I decide to convert the mill, I am thinking something like the ama25lv, its about the right size to get behind my shed!
This means I am back to idea 6 albeit with a conventional Z but I have measured the area where I am building my 'workshop' and once I have fitted soundproof / insulation I will be left with a working area of about 1.6m wide by 4m long. If i install my router flat then that will leave only 60cm at best to get past the machine, Is this too tight? it could be quite dangerous with the gantry swinging back and forth!
My other option would be to install it against the wall length ways or height ways and bolt to the floor, height ways would work best for me but that depends on the recomended gradient and the lump of concrete its bolted to!
Can you take a look at my Y carriage arrangement and let me know if it will be OK, I moved the lower carriages together by 50mm and the upper ones 50mm further apart so it utilises the space on top of the beam and gives me some of the movement back which was lost by using the conventional Z.
Things to do:
1. Build my shed/workshop
2. Buy a milling machine
3. Build my router!
4. convert the milling machine?

Cheers, Charlie

[CharlieRam]

Well here it is, Idea 9 , mainly for woods/plastics but also hoping to do a bit of aluminium or cast iron work when I modify my mill (which I havn't actually got yet! )
All bits in blue are steel, the gantry is built using 80x40 4mm box section aluminium with a 20mm plate across the front, the X axis rails will be 80 x 40 steel with 5mm of resin for leveling but I am not sure whether to go 3mm or 4mm steel thickness (is 3mm enough, I will go 4mm if its weldable??) the frame is 50x50 3mm steel and I plan on putting 4"x1" aluminium box section running the length of the bed with a 10mm alu plate on top of that drilled and tapped.
To manufacture the gantry I plan to machine the front plate, leaving a little for finishing. The aluminium box section will then be bolted together, solid aluminium blocks will be machined to fit in the ends. I am then hoping to lightly skim the X rail seating faces square to the front face and also lightly skim the front face before attaching the 20mm plate. I will then skim the profile rail support faces on the alu plate. What do you reckon?
The frame and X rails are all one component and even though I haven't welded before I am hoping to get the top face for the rails within 5mm so that the epoxy leveling will do its job! I realize that I am going to have to shim the ballscrew mounts so that they run parallel with the rails but is there anything else I should watch out for?
I have included the sketchup file for anyone wanting to tear it apart for scrutiny and as always appreciate any feedback as to why it will/won't work.
Cheers, Charlie

[Boyan Silyavski]

I wouldn't put that profile at the back, that limits larger pieces. Instead cut 2 more small side pieces and reinforce the last one of the stair steps at the back of the table, welding a pack of 2 together. Same for the front. may be even one more at the middle. Or reinforce back and front with additional plates.

How long and how wide is the table? may be if you remove what i say you will need adding it bellow, even at front also. Depends on your priorities. Tough i see at the other hand you use a lot of diagonals, so that last may be not necessary.

[CharlieRam]

The machine overall size is 950 wide by 1550 long with a cutting area of 610mm x 1300mm x 150mm
The upper cross brace is also used to mount the stepper but I can add more strutts between the x rail and 50mm frame if thats what you mean?

[ba99297]

Hi
First of all be polite with my English

About your plan
I think that the tube where the rails rest, should be wider (60mm at least ). When you apply the epoxy you will need 20mm for the rail and 15mm-20mm left right of the rail for the meniscus effect ( the tension that has the epoxy at the edges ) . So your tube should be at 50-60 wide minimum)

At the top view I saw 8 diagonal braces. I think you will need only 4 at the edge corners.
I see that you have the y axis ball screw at the middle protected by a plate. Think how you are going to work install and adjust the ballscrew as many time we think “I will think about it later” and finally you find out that you cant even bolt is in place”


Things you must be careful (others told me do so and they are right)

Spot weld in order not to produce too much heat. Even with 80X80X4mm distortion is an option ). After the frame get a first shape you can make bigger welds, no more 3-4 cm at a time. I know everybody want to make big weld with many amperes at the arc welder but this produce too much heat.
Try to be as accurate as possible at every step, even if you finally apply epoxy. Of course don’t make excesses.


It is very similar to mine machine that I design for about a year and start to build 2 months ago


My build starts at page 12 of the thread

http://www.mycncuk.com/threads/6674-...-please/page12

My main specs are
80X80X4mm tube for frame and gantry (gantry at the middle has a piece 120X60X3mm )
80X40X3mm steel tube for the bed.
Working area
750 X 1400 X 180mm

4 Yaskawa 400 watt servos (2 for x axis )
20mm profiled rails

The design of the table was mainly based on syliavski construction.
Also the one who help me most is Dean. I change my mind many times, I get the basic idea for the table from Syliavski, Dean answers all my questions and I think that I make a good start. Of course i made mistakes. I think it is very difficult to avoid mistakes at the first construction. It is very important to have people that inspired you by their ideas, also people who are there to help whenever you have a question.It would be wrong if I didn’t mention the help of Jonathan for his servo size calculator, and Eddy Current for his information and all the people that ansewr to my thread.

Finally I want to suggest you to think how you are going to move that monster. First things are easy but as you add weight it would be difficult to move and turn the frame. Mine now is nearly 250kgr. If I didn’t install a winch it would be a nightmare to move it. You can see the photos to understand what I mean

. http://www.mycncuk.com/threads/6674-...-please/page13


Have a good start

Vagelis

[CharlieRam]

Hi, I did read about the meniscus effect but I am sure I also read that 10mm either side was enough which is why I went for the 80x40, I could lose the 4 inner angle braces and possibly use the spare material to add another cross brace. It is very similar to your design except yours looks a lot stronger, my ballscrew is actually bolted to the front ecocast plate and so 'should' run parallel to the rail front face meaning I only have to adjust up/down, a couple of holes through the box section gantry should enable me to adjust that unless you can get bearing supports that are threaded?
Yes the frame will be heavy but not as heavy as yours, I will need one length of 80x40x4 and 2 lengths of 50x50x3 which I believe will come to just under 120kg, that is without ballscrews etc so should be managable for a couple of people.
I've never welded anything before so I will be practicing first but I have read about spots and little bits at a time so wish me luck on that!
Cheers, Charlie

[Boyan Silyavski]

Yes,about the epoxy, the 10mm at each side is ok, given that you weld to the mm the frame.

i also am wondering about that diagonals and at the same time big holes in the middle. I don't know the top you are planning on but generally i wouldn't have a hole in my table bigger than 300mm, otherwise you will need 50-70mm top if made from ply or similar. even alu top would benefit from such maximum distance.


IMHO you are mistaken about the ball screw end mounts. Do yourself a favor and design it similar like i did them from 10mm plate and additional plates that screw to that perpendicular reinforced with ribs plate.
Or you could find your self in a scenario that you have to file shims or even worse, what you will do if the ball screw has to go inside direction?
I believe the way i did it was simpler especially for precise alignment of the ball screws. Meaning that when gantry is mounted and squared, i just screw the nut to the nut plate and moved the gantry one side by hand. Screwed the ball screw mounts, then repeated at the other side. Then tightened. So no fiddling with alignment and so.


About the welding i also have not welded before. Played around a bit , watched some videos on YouTube and was good to go. Just remember- if arc or mig welding the most important thing is to keep the arc at the same distance and watch the pool and spread it, not think about quality, instead think about welding strong with good penetration. just zigzag to ensure penetration.

[CharlieRam]

i also am wondering about that diagonals and at the same time big holes in the middle. I don't know the top you are planning on but generally i wouldn't have a hole in my table bigger than 300mm, otherwise you will need 50-70mm top if made from ply or similar. even alu top would benefit from such maximum distance.

I will add another cross beam, maybe 2 then if I have enough material, as I mentioned earlier the plan is to put 4" x 1" 3mm alu box section over the length of the bed and then 10mm alu plate on top of that drilled and tapped.

IMHO you are mistaken about the ball screw end mounts. Do yourself a favor and design it similar like i did them from 10mm plate and additional plates that screw to that perpendicular reinforced with ribs plate.
Or you could find your self in a scenario that you have to file shims or even worse, what you will do if the ball screw has to go inside direction?

I understand what you are saying but so long as the rail seating faces are parallel to the bearing block seating faces and the bearing blocks are machined correctly then I will only have to adjust the distance to the Z plate which I am hoping to adjust with the ballnut housing bracket, out of interest how accurate are the ballscrew end blocks from base to centre height? If the heights are out I can always grind them at work while no one is looking!
Cheers, Charlie

[CharlieRam]

Does this bed design look better? It is still made using 1 off 80x40x4mm 7.5mm long and 2 off 50x50x3 7.5m long steel.

[Boyan Silyavski]

I see it better.

I measured the ball screw mounts i use/chinese/ . They are 0.01mm precise.