Project Beaver

[OMLCNC]

Project Scope: To build a CNC Router capable of cutting English Hardwood and Aluminium at speed. (faster than I can machine in Jigs and fixtures) with accuracy and good finish. Capable of using large profile bits,50mm diameter and full depth single parse cuts (Dovetails currently 32mm but would like to do bigger).


The Design: (Fall about laughing if you like but just another thank you to the forum for allowing me to copy from other members, you will recognize who you are).

Outline: Footprint to be 1200 x 1200mm, Machining area (Red)1150 x 600mm, Machining overhang 100mm (For cutting dovetails as shown, possibly two components at once, am I mad!).
Size determined by space in workshop, I do make larger work but can let it hang outside machine area.

Component Guessing:
Welded Frame 80 x 80mm steel box section, Adjustable Feet
Welded Bed 50 x 50mm steel box section.

X axis:2 x HGR20 Rail x 1200mm, 4 x Hiwin HG20 carriage (on epoxy levelling),
2 x RM1610 Ballscrew x 1150mm (Nut, Bearings etc), 2 x Nema? Motors, 2 x Pulley Set , 2 x Belts.

Y Axis: 2 x HGR20 Rail x 850mm, 4 x Hiwin HG20 carriage, On 2 x 45 x 90mm Aluminium Profile. 1 x RM1610 Ballscrew x 750mm (Nut , Bearings etc), 1 x Nema? Motor, 1 x Pulley Set, 1 x Belt.

Z Axis: 2 x HGR20 Rail x 400mm, 4 x Hiwin HG20 carriage, On 20mm Aluminium Plate. 1 x RM1605 Ballscrew x 350mm (Nut Bearing etc), 1 x Nema? Motor, 1 x Pulley Set, 1 x Belt.

All other components from 20mm Aluminium Plate.

Spindle – has to be ER20, water cooled, 3Kw?

Review: Suggestions and feedback welcome on design.

Issues to be resolved:
1. Do I want an adjustable bed ? - Pros and cons?
2. Overhang at end of machine? - Right, Wrong, Better suggestions?
3. Motors, what size?
4. Can I put off doing electrics/computer side of thing until I have finalised design?

I will not be purchasing anything until final design completed and every component drawn, nuts bolts etc and simulated assembly carried out. To make sure it can be built.

[Clive S]

Issues to be resolved:
1. Do I want an adjustable bed ? - Pros and cons?
2. Overhang at end of machine? - Right, Wrong, Better suggestions?
3. Motors, what size?
4. Can I put off doing electrics/computer side of thing until I have finalised design?

Looks like you have done your homwork
1) My machine is quite similar to yours with an adjustable bed. But I have never had any occasion to alter it, I you do alter it you have to get it level again and resurface.

2)That to me seems OK.

3) Nema 23 all round with low inductance and decent drives (AM882 or EM806) are good BUT think about moving them to the back of the machine and (if I had my time again) change the X to 1 x nema 34 and use long belt for the two screws. This give you a better choice of motion controllers and less problems with homing etc.

4) I would not buy or start any of the electric stuff until the main frame is built as things change over time.

Good luck with the build.

[OMLCNC]

Thanks for the advice and feeback Clive



3) Nema 23 all round with low inductance and decent drives (AM882 or EM806) are good BUT think about moving them to the back of the machine and (if I had my time again) change the X to 1 x nema 34 and use long belt for the two screws. This give you a better choice of motion controllers and less problems with homing etc.


I will have a redesign based on your comments, stick with fix bolted bed that could be movable in the future to cover all options.

[Clive S]

I have about 4 positions that I can mount my bed in (bolted) But never need to move it. machine 1600 x 1000

[Nr1madman]

Hello! Your design is very similar to the one I am building. Real nice work!

Have a doubt about the y axis being 45x90 profiles, even if used in L formation I think it might be to flimsy for fast alu cutting? Please correct me if wrong :)

[JAZZCNC]

Have a doubt about the y axis being 45x90 profiles, even if used in L formation I think it might be to flimsy for fast alu cutting? Please correct me if wrong :)

Ok Your Wrong.!! . . . . Why would you say such thing without any experience of using this arrangement.?

I can tell you with absolute confidence, mostly because I came up with the design, and have tried and tested on dozens of machines that it easily handles aluminium in this arrangement.

[Boyan Silyavski]

Ok Your Wrong.!! . . . . Why would you say such thing without any experience of using this arrangement.?

I can tell you with absolute confidence, mostly because I came up with the design, and have tried and tested on dozens of machines that it easily handles aluminium in this arrangement.

Before i was thinking exactly the same as Nrmadman, but remember once after your statement in another thread , i sat down and did the numbers looking at profile manufacturers data, and it seems you are right about the strength being enough and comparable with steel gantry.

[JAZZCNC]

Before i was thinking exactly the same as Nrmadman, but remember once after your statement in another thread , i sat down and did the numbers looking at profile manufacturers data, and it seems you are right about the strength being enough and comparable with steel gantry.

But that's the difference Boyan.? I Won't and Don't give advise on anything unless I have actual experience and know it works.
People need to realise that at DIY level the calculations mostly don't apply. Yes can't get away from pyhsics etc but most calculations are based on ridgid values and strict rules. They don't account for the DIY affects of muppets like US in working in sheds.

My thoughts on Calculations are don't waste the time,!! Instead invest the time looking for Real world examples and ask the person who made it what would do better.
The best Machines I've seen built have been built using just 3 Goods.?? . . . . . . . Good research, Good attention to detail and Good Old Common Sense.

[Nr1madman]

Also I think you may benifit with more bracing by the x rails and bed.. :)

[OMLCNC]

Also I think you may benifit with more bracing by the x rails and bed.. :)

I agree, and will add some more, but this morning Sketchup seems to have a mind of its own, I am still learning about it.
Will post revised design.

Your other point about y axis being flimsy, possibly true, but I only want to cut wood at speed. Should I change to steel? Any builds to look at?