-
3 Attachment(s)
Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
So I've been planning to build this thing for quite some time now, finally I have taken the plunge and started to finalise the specs. I have read, re-read and read again many of the posts on here looking for advice and ideas, and I am now ready to lay out my designs in front of you guys for some no doubt frank but highly constructive criticism hehe!
My machine will be used for every type of material between balsa (model making) and Aluminium, and must be able to cut 1220mm x 2440mm sheets of the above materials at times. I will type out my specs a little later on as I'm limited on time at the moment, but I have put together the design in Sketchup for the general idea, and wondered before I go any further if you can give me ideas as to whether it will be strong enough or not?
Attachment 11089Attachment 11090Attachment 11091
-
Re: Advice on a mammoth CNC Router build please guys!
It looks quite strong but you don't have any diagonal bracing on the ends. Also with a machine this size I would estimate the amount of material and calculate the weight, you will probably find it need to be made in bolt together sections, the bed being one section on it's own. The method of bolting may therefore have a small effect on your current design. It also looks like you have very little depth of cut in the Z direction.
These threads are worth reading.
http://www.mycncuk.com/forums/router...on-please.html
http://www.mycncuk.com/forums/router...t-build-3.html
-
Re: Advice on a mammoth CNC Router build please guys!
Thanks pal, yeah I read both of those threads as part of the planning stage for this build. The Bed will be bolted together in the three sections shown. I will try to incorporate some diagonals too, thanks for that advice. As for the Z axis, what do you recommend? I did think about putting another length off 100x100 between the carriage and the Y axis, to lift it a little further but wasnt sure??
-
1 Attachment(s)
Re: Advice on a mammoth CNC Router build please guys!
This is the side arrangement I went for, the linear rails sit on top of the upper blue beam, top of the bed will be flush with the top of the lower blue beam.
Attachment 11102
The top rail bolts to the bottom section via those red flanges, this allows me to level up the top faces using shims or compressing epoxy putty in the joint.
I'm planning on 150 to 200mm for Z travel, you have to account for your longest and shortest cutters plus your workpiece thickness plus any sacrificial beds you might add in.
-
1 Attachment(s)
Re: Advice on a mammoth CNC Router build please guys!
Thanks for the comments. I have made a few adjustments to the design based on comments made and also my own thoughts (dangerous!)
I have added a second 3m length of 100mm x 100mm box along the top, this gives me around 200mm on the Z axis. The plate of Aluminium on the bed will be 20mm thick and surfaced flat. I will set the rails along the 3m steels on Epoxy as in Jonathan's build so they are as true as possible, and the Bed will also be supported with uprights rather than diagonals, purely because the frame must bolt together and it is easier with uprights than diagonals to do so, without hopefully compromising the overall strength, I can add feet below the uprights if you deem it sensible too?
Let me know your thoughts guys as I would like to start on the frame soon. Ignore the frame for the Z at the moment, its in its very very early sketchup stages and will change A LOT from now...
Thanks in advance!
Attachment 11191
-
Re: Advice on a mammoth CNC Router build please guys!
I wouldn't use that method to build it.? I would drop the extra top rail and just extend the uprights to get your extra height.
It will save on material and resonance because those will be 2 large drums you'll be creating. To be honest I wouldn't use 100mm Box I'd go with 80mm and thick walled.
I'd use the design Eddy showed with top rails sat on plates which can be adjusted into plane much easier. The work involved with Epoxy is quite involved and to be honest a complete waste of effort if your going to use those Cheap round rails has there will be more error in there base than the surface your fastening to.! . . . . I also doubt you'll get it any better with epoxy than using the above method and it will take much longer and not be has flexible, it will also cost lot more money.
Show us the same picture but with out the bed base so can see the bracing etc.
-
Re: Advice on a mammoth CNC Router build please guys!
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.
-
Re: Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
Ok I will spend some time converting it all to 80mm box, what wall thickness would you recommend?
Those rails are only for an idea of where everything will go, in the end I will use Hi-Win rails all round as I have read a lot about there flexibility in use and strength, I just couldn't find a model of then in Sketchup so put the SBR's in just for reference. My main priority is getting the frame completed as I would like to do the build in phases.
If I extend the uprights and use the plate method to true it all, will five uprights be enough/too many? Or should I leave that as is?
Also, should I leave the bed in 100mm box as surely that will need as much strength as possible?
Thanks in advance guys appreciate the time taken to help!
-
Re: Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
Hi M8
with such a large machine i think resonance could be an issue, i think Jazz commented on another build and suggested loosing the symetry of the supporting members, i am sure he will comment shortly.
regards
Mike
-
Re: Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
Quote:
Originally Posted by
mekanik
Hi M8
with such a large machine i think resonance could be an issue, i think Jazz commented on another build and suggested loosing the symetry of the supporting members, i am sure he will comment shortly.
regards
Mike
Hi Mek,
I considered this whilst planning it all, all boxed sections in the side of the frame would be filled with sand, and then the holes plugged afterwards, including the diagonal braces, would this be enough to damp the resonance?
-
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!!
-
2 Attachment(s)
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.
-
2 Attachment(s)
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
-
Re: Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
Quote:
Originally Posted by
Wejjmeister
expand on the disadvantages??
If the rails are on the bottom surface then the bearings, i.e. your supporting points, are closer to the tool/bed. The overhang is therefore reduced, so the stiffness is correspondingly higher. It does however make mounting them on epoxy more challenging - although you could conceivably mount the Y rails and X bearing blocks on the same epoxy leveled surface and get very good accuracy. I'd try drawing both orientations and see which looks the most promising.
Quote:
Originally Posted by
Lee Roberts
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?
I tend to agree - there becomes a point when an extra couple of mm of epoxy doesn't cost much compared to the added material/time required to get the frame more accurate. The epoxy is pretty strong/hard and the damping properties may be useful, so I wouldn't be too concerned about minimizing the thickness, within reason. If you look in my build log the epoxy is quite thick, but don't treat that build log as gospel - there's plenty of room for improvement.
-
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.
Thanks Eddy, any idea why this happened or?
Quote:
Originally Posted by
Clive S
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
Hi Clive, in your picture to make your epoxy "gutters" you look to have used MDF, i dont know if you've seen Jonathan's recent machine but he made his using aluminum and then left those in place once the machine was ready. My question is, what are the edges like on the epoxy once it "sets", i.e dose it need protecting from damage and so on to keep it together.
Did you do anything to yours after the machine was ready to be used to keep it safe?
Quote:
Originally Posted by
Jonathan
I tend to agree - there becomes a point when an extra couple of mm of epoxy doesn't cost much compared to the added material/time required to get the frame more accurate. The epoxy is pretty strong/hard and the damping properties may be useful, so I wouldn't be too concerned about minimizing the thickness, within reason. If you look in my build log the epoxy is quite thick, but don't treat that build log as gospel - there's plenty of room for improvement.
Thanks JB, I didnt see your post untill i posted mine.
.Me
-
Re: Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
Quote:
Hi Clive, in your picture to make your epoxy "gutters" you look to have used MDF, i dont know if you've seen Jonathan's recent machine but he made his using aluminum and then left those in place once the machine was ready. My question is, what are the edges like on the epoxy once it "sets", i.e dose it need protecting from damage and so on to keep it together.
Did you do anything to yours after the machine was ready to be used to keep it safe?
It is 10mm MDF the box section is 60x60 the MDF is placed right on the edge (just on the round part of the box) and then a very thin bead of silicone was run around the inside of the moat to stop any leaks. I also rubbed a little oil on my finger and ran that around to stop the epoxy sticking to the MDF.
The epoxy is like water and runs around ok. When it was cured the MDF was removed (the epoxy creaps up the inside of the MDF a little) Then I used a scraper and a flat file to get rid of the edges that were raised, it is easy to see when you are scraping it because it will start marking the centre.
The rails were then screwed right through the epoxy into the steel. Job done. The epoxy can be chamfered off at the edges as it can be very sharp like glass. ..Clive
-
Re: Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
I've used both methods in the past and each work good and each have there own +/-
Full Epoxy level is ok and works good but has you can see with clives pictures there's plenty of prepartion required and on large machine like what the OP wants this means a lot of work. This prep has to be very good and fully sealed other wise sag can happen and being 3mtr length the chances of this happening are plenty.
Yes it's not the end of the world and can be corrected if it happens but it's a ball ache when it happens.!! . . . . I'm sure Both clive and Jonathan will tell you when pouring and it starts leaking your running round like headless chicken trying to suppress it and again over 3mtr and between 80-100mm width that's a fair amount of epoxy your fighting with.! . . . . It's also not cheap.
Now with Epoxy putty feet and shims you don't have this problem has there's no liquid epoxy involved but you do still have to do careful measuring and setting up to get rails on same plane. Unlike The above epoxy method which takes care of this for you, thou if it's not perfect which you won't really findout until machine is built and working then it's a lot more work to correct.
The epoxy shimming is very easy to correct on the fly and while machine complete and working. You don't need to strip it down to correct.
Now to be honest I think the OP is correct to use Both methods has 3mtr is a long length of boxsection to ensure is straight and true, which it won't be, so would need some work even with Epoxy putty method and the Epoxy liquid method will make light work of this. The Epoxy putty and Shims will give him the fine tuning he will need over this length machine.!!
-
Re: Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
Quote:
Originally Posted by
Clive S
It is 10mm MDF the box section is 60x60 the MDF is placed right on the edge (just on the round part of the box) and then a very thin bead of silicone was run around the inside of the moat to stop any leaks. I also rubbed a little oil on my finger and ran that around to stop the epoxy sticking to the MDF.
The epoxy is like water and runs around ok. When it was cured the MDF was removed (the epoxy creaps up the inside of the MDF a little) Then I used a scraper and a flat file to get rid of the edges that were raised, it is easy to see when you are scraping it because it will start marking the centre.
The rails were then screwed right through the epoxy into the steel. Job done. The epoxy can be chamfered off at the edges as it can be very sharp like glass. ..Clive
Thanks Clive, I liked the tip on silicone, will add that to the mental archive for when the time comes. Good idea on the chamfering, i was thinking about what i could use to protect it once done but it sounds like its quite durable.
Clive, where is your build log?
.Me
-
Re: Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
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.
Quote:
Originally Posted by
Lee Roberts
Thanks Eddy, any idea why this happened or?
Because I assumed my garage floor was level and I just built it from that datum.
-
2 Attachment(s)
Re: Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
Attachment 11219Attachment 11220
First stage of the MkII done, Im still working on it so bear with me. I decided just to use the epoxy on the tops of the rails as plates and shims plus epoxy will be a mare. It may be slightly better but I dont intend on moving it once set up so I think Epoxy should suffice.
The whole of the frame will be sand filled too, so not worried about resonance.
Next step is the rails and ballscrews and placements of. Will add more a little later hopefully, time permitting!
Thanks ever so much for all of the comments though guys, a real help!
-
Re: Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
The diagonals at the sides, it seems to me help nothing except add weight. Should work fine without them, but that's me :-)
-
Re: Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
Looks ok... but probably a bit OTT. Don't leave the ends of the long pieces of box section cantilevered - support them with a piece at 45°.
Quote:
Originally Posted by
JAZZCNC
I'm sure Both clive and Jonathan will tell you when pouring and it starts leaking your running round like headless chicken trying to suppress it
I've not had any leaks at all. The guiding aluminium strips were firmly bolted to the frame, and the wooden pieces used covered with grease, which makes a good seal, and clamped with plenty of G-clamps. If it had leaked then I would have addressed the situation in a calm manner, using the glue gun and tape I had on hand just in case. The running round can be left to the three birds in the garden...
-
Re: Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
Sorry for interrupting but I have an idea
Could it be possible to combine both methods (epoxy and shims) BUT instead of epoxy use clear coat for car painting. The clear coat will be the mean to show us which is the true level between the rails, so then we put shims and putty and fit the rails on that level. For that size of machine that may be 2-3 kgr of epoxy will be needed, the difference to the final cost will be significant After the putty pures we could even took off the clear coat as I don’t know how strong it is in getting pressure from the rails. In that way we don’t pay too much money for the epoxy as I think clear coat is much cheaper and we won’t waste too much time to true level the rails as we use the clear coat as guide. Regards the pure time of clear coat we could use a catalyst that will make pure time longer.
Also instead of clear coat we could use anything chaper that has self leveling properties
Just an idea I don’t know if it is correct
Vagelis
-
Re: Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
Quote:
Originally Posted by
silyavski
The diagonals at the sides, it seems to me help nothing except add weight. Should work fine without them, but that's me :-)
Even if there was 3 each side, one at each end and one in the middle, or even 2 each side, one at each end, that would be enough.
-
Re: Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
Quote:
Originally Posted by
ba99297
Also instead of clear coat we could use anything chaper that has self leveling properties
water ?
But the idea with epoxy is that it finds it's own level then hardens to that level and job done, with the method you suggest how would you measure the depth of clear coat (water) to know that the frame underneath was level ?
-
Re: Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
Quote:
Originally Posted by
EddyCurrent
water ?
But the idea with epoxy is that it finds it's own level then hardens to that level and job done, with the method you suggest how would you measure the depth of clear coat (water) to know that the frame underneath was level ?
What i suggest isn’t so different with the epoxy method. Clear coat is also a resign but I think much more cheaper that will harden when it cures. Water isnt hard unless it becomes ice. Water could give us a perfect level but the question is how we could “capture” that level. What about self levelling floor resigns ?
-
Re: Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
ba99297, Sorry, it sounds like I did not understand what you meant with the clear coat, I did not think there was enough strength in clear coat when it hardened.
-
Re: Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
Quote:
Originally Posted by
Jonathan
I've not had any leaks at all. The guiding aluminium strips were firmly bolted to the frame, and the wooden pieces used covered with grease, which makes a good seal, and clamped with plenty of G-clamps. If it had leaked then I would have addressed the situation in a calm manner, using the glue gun and tape I had on hand just in case. The running round can be left to the three birds in the garden...
Oh I'm sure I'd read somewhere you had a Leak.??. . but obviously not so I stand corrected you obviously don't know.!! . . .But I assure you that you would run around trying to stop a leak if it happened no matter how COOL . . :hysterical:. . . you think you are.!!
-
Re: Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
-
Re: Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
Quote:
Originally Posted by
ba99297
What about self levelling floor resigns ?
The problem comes from the type of resin.? I think Car paints and self leveing Floor paints which are manily polyester resins contain high solvent levels which evaporate and can cause sinking etc.
-
Re: Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
Quote:
Originally Posted by
JAZZCNC
The problem comes from the type of resin.? I think Car paints and self leveing Floor paints which are manily polyester resins contain high solvent levels which evaporate and can cause sinking etc.
They wont shrink or sink but they do not harden to the same levels as paints are meant to be somewhat flexible to resist cracking etc, so it wouldn't be suitable for this particular job as it would 'give' unlike the epoxy resins used in these forums before which cure fully.
-
Re: Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
Quote:
Originally Posted by
EddyCurrent
Even if there was 3 each side, one at each end and one in the middle, or even 2 each side, one at each end, that would be enough.
Should I remove these then? Im all for saving material, especially considering the prices of steel these days!
-
Re: Advice on Mammoth CNC Router Build - Steel Framed - 2440mm x 1220mm cutting area!
Quote:
Originally Posted by
Wejjmeister
They wont shrink or sink but they do not harden to the same levels as paints are meant to be somewhat flexible to resist cracking etc, so it wouldn't be suitable for this particular job as it would 'give' unlike the epoxy resins used in these forums before which cure fully.
I belive it does shrink and it's why Only Solvent free Epoxy resin is used for Epoxy Granite to avoid voids, sinking and cracks appearing when solvent evaporates.!!
Regards the steel and bracing then yes you could reduce quite a bit of that steel.