Re: Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
Hi
I am a new to this game and was just passing on information i have picked up from the forum, Jazz uses sand filled sections, for a definitive answer you might be better waiting for advice from our senior members that have actually built and used a machine(hint)
Regards
Mike
Re: Advice on a mammoth CNC Router build please guys!
Quote:
Originally Posted by
silyavski
On your last picture it seems you were thinking mainly of cutting aluminum :loyal: . If you continue with this design, take care that the rails on the gantry should be maximum low, near towards the table and as round rails don't like that position nor milling aluminum something has to change there, for starters -square rails.
Would it be better to place the rails (HiWins) on the underside of the gantry then? I can incorporate this into my changes too if so? The issue then will be travel...hmm!!
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Re: Advice on a mammoth CNC Router build please guys!
Quote:
Originally Posted by
Wejjmeister
Would it be better to place the rails (HiWins) on the underside of the gantry then? I can incorporate this into my changes too if so? The issue then will be travel...hmm!!
Hi Wejjmeister,
The ideal rail arrangement for these types of rail (supported round) is like what you see in the first pic below on the Y Axis (machine bed), so what your looking for is the base/bottom face of each rail to be facing each other. This dose make it harder when you come to true the rails to each other and get them on the same plane's but it is feasible.
This is true for any axis you use this type of rail for, so if you look at pic two below i'm selected in green the faces I think you should use to mount your rails. If you mount them on those faces, the other nock on effect is that you are also bringing the gantry closer to the bed.
.Me
Re: Advice on a mammoth CNC Router build please guys!
Quote:
Originally Posted by
Lee Roberts
The ideal rail arrangement for these types of rail (supported round) is like what you see in the first pic below on the Y Axis (machine bed), so what your looking for is the base/bottom face of each rail to be facing each other.
Except, as specified in post #8, he's not using supported round rails. Most Hiwin (or similar) type rails have equal load ratings in both directions, so just mount them in the way you think is easiest. How they are orientated in the current drawing is not a bad idea as you can use epoxy to level all the surfaces, but there are some disadvantages.
Re: Advice on a mammoth CNC Router build please guys!
Quote:
Originally Posted by
Jonathan
Except, as specified in post #8, he's not using supported round rails. Most Hiwin (or similar) type rails have equal load ratings in both directions, so just mount them in the way you think is easiest. How they are orientated in the current drawing is not a bad idea as you can use epoxy to level all the surfaces, but there are some disadvantages.
Bugger missed that post, o well its their for everyone else then lol, thanks Jonathan.
So, are you going to go as far as epoxy Wejj or just shim the rails when the time comes?
.Me
Re: Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
Epoxy I think although I will also be taking a leaf from Jazz and making it so the 3m lengths can be shimmed to give a better starting point, then on with the epoxy!! Funtimes!
So to clarify, I can mount HiWins as in the initial design i.e on top of the rails.
Jonathan, can I trouble you to expand on the disadvantages??
Thanks guys!
Re: Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
Quote:
Originally Posted by
Wejjmeister
Epoxy I think although I will also be taking a leaf from Jazz and making it so the 3m lengths can be shimmed to give a better starting point, then on with the epoxy!! Funtimes!
So to clarify, I can mount HiWins as in the initial design i.e on top of the rails.
Jonathan, can I trouble you to expand on the disadvantages??
Thanks guys!
I don’t know if I’ve misunderstood Jazz here or you with regards to shimming...
Surly enough accuracy can be achieved when cutting and then wielding the frame that any small differences would be "levelled" out from doing an epoxy bed for the rails to then sit on?
To confirm, what it sounds like your suggesting is, having the ability to “shim” the 3m lengths, along their lengths.
.Me
Re: Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
Quote:
Originally Posted by
Wejjmeister
Ok I will spend some time converting it all to 80mm box, what wall thickness would you recommend?
I would say 5mm, it's quite heavy but if you are attaching rails directly to it then you need some thickness for the screw threads. I used 3mm box so I'm having to glue a piece of 6mm flat strap inside to give it a 9mm thickness. The best way I've found to decide on material thickness for threads is to see what thickness a nut is for any particular size bolt and use that as the minimum.
Re: Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
Quote:
Originally Posted by
Lee Roberts
I don’t know if I’ve misunderstood Jazz here or you with regards to shimming...
Surly enough accuracy can be achieved when cutting and then wielding the frame that any small differences would be "levelled" out from doing an epoxy bed for the rails to then sit on?
To confirm, what it sounds like your suggesting is, having the ability to “shim” the 3m lengths, along their lengths.
.Me
That's the method I'm also using and I found that after welding, one corner of the frame was 3mm out of level with the other. This might be regarded as too much depth for epoxy treatment alone. I don't know for sure ? but at least I can shim the rails to as near level as possible then use epoxy from there.
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Re: Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
Quote:
Originally Posted by
EddyCurrent
That's the method I'm also using and I found that after welding, one corner of the frame was 3mm out of level with the other. This might be regarded as too much depth for epoxy treatment alone. I don't know for sure ? but at least I can shim the rails to as near level as possible then use epoxy from there.
Eddy You might have seen this before there is no problem with the thickness of the epoxy Jonathan and I have used it I think Dean uses some sort of epoxy putty which is stiffer, he has explained that on other threads.
I poured this to about 5mm deep it is very slow setting 10 - 20 hours and don't touch it for 48 hours. Wests system
..Clive
