[Mogilogi]

Hi Mogi - I'm starting to think about Milli again and have done some generative work in Fusion360. Does Solidworks have generative functions? Peter

Hi Peter, is this what you mean ?
https://m.youtube.com/watch?v=XcXENyRUcQA

[ardenum2]

you can cut steel with a router, but its gonna be at a level of a dental mill, that is tiny tools, very high speeds, 20k+ rpm. Stiffness is key to any performance. If you want to cut steel with a langmuirs copy, I have very bad feelings about that. If you want to cut steel faster you need a different frame for that. If you want absolute best performance at a budget, you need a double column raising gantry.

What's your budget and what kind of accuracy do you want? Do you want to produce parts for fun? or occasionally as a jobshop? There's plenty of options. We can guide you but we need more data.

Yes, Pete, solidworks has generative design and topology optimizition. But it deals very poorly with meshes, I mean, it barely even works with them. Think things like lag, stutters and crashes if the mesh has any decent amount of polygons. Meshes are a nightmare to work with in sw.

[Mogilogi]

What's your budget and what kind of accuracy do you want? Do you want to produce parts for fun? or occasionally as a jobshop? There's plenty of options. We can guide you but we need more data..

Hi Ardenum, About budget, mostly I'm thinking about the steel price and how much it will take to prepare it, hardware I will use what I bought already, at the same time I'm trying to build a machine that is copy to langmuris, to cut parts for fun mostly will be granite engraving, aluminum, it would be good if I can cut steel like langmuris, if I can get it to get better than them would be even better, also occasionally as a jobshop I would like to cut parts for university students.

Stiffness is key to any performance. If you want to cut steel with a langmuirs copy, I have very bad feelings about that

is that because langmuris machine is not stiff enough ? or because I can't copy it good

If you want to cut steel faster you need a different frame for that. If you want absolute best performance at a budget, you need a double column raising gantry.

You mean the Y rails should be supported and connected to the bed ? like this

[ardenum2]

.
no I meant when the gantry moves up and down instead of the spindle like in the usual Z axis assembly. Like this:

https://www.youtube.com/watch?v=0yFKaCn9soo

If you want to built from steel, can you get structural square pipes? Like these?(https://stahlshop.de/stahl-produkte/...profile?page=8) It would be straight forward to build such a frame from square pipes and there would be minimal welding(or stich welding) involved or you could braze them to avoid deformation. Unless you can stress relief at a company if thats cheap.

"is that because langmuris machine is not stiff enough?" yes it's barely stiff enough to cut anything

[Mogilogi]

.
no I meant when the gantry moves up and down instead of the spindle like in the usual Z axis assembly. Like this:

https://www.youtube.com/watch?v=0yFKaCn9soo

Hi arden, wow that is impressive machine, i wouldn't even dream to have one like that or even close, this design is good and more stable i'm sure, maybe my next machine would be from this type

If you want to built from steel, can you get structural square pipes? Like these?(https://stahlshop.de/stahl-produkte/...profile?page=8) It would be straight forward to build such a frame from square pipes and there would be minimal welding(or stich welding) involved or you could braze them to avoid deformation. Unless you can stress relief at a company if thats cheap.

There is some companies that are selling that kind of structural square pipes in my country, but they only sell it as 6 meter long and i only need 1 meter, so going with combining plates together is the easiest way, about stress relief i'm searching for a company that can do that, if i could't fine, i'm planning to build my own stress relief furnace maybe that can be an option, similar to this one

yes it's barely stiff enough to cut anything

Is this not good, i don't have good experience with milling steel, that is why what i saw looks good for my use case and what i'm thinking i can be doing with the machine.


by the way my main job is a Mobile App Developer, this CNC stuff is my hobby, i like to build things + i have young boy children i want them to grow seeing that kind of stuff and be interested in it to grow their imagination.

[ardenum2]

to build an oven the size you need is ambitious within itself. You need to SR the entire machine in one go, then you need someone with a big mill to finish machine it. We have a forge at out mens shed and its hard enough to get small things to red... Getting a machine up to red, do you have a small power station at home? Lots of research to do yet. Peter

double column gantry would be easier to stress relief since its made from 4 long and relatively thin columns, the bed could be cast from non shrink grout, in the same way you'd cast a machine foundation.

Is this not good, i don't have good experience with milling steel, that is why what i saw looks good for my use case and what i'm thinking i can be doing with the machine.

That actually looks quite good for how the machine is build, you can hear the vibrations from the sides though.

[joeavaerage]

Hi,

Hi Joe, I'm not planing to cut steel all day long, I need the machine to do it with even lower feed, when I need it, to get me started so I maybe after this machine I build a better.

Been there, tried that....and failed. Either a machine is rigid enough to cut steel, or its not. My experience is that no matter how slow and gentle you cut as soon as you start making
steel chips the cutting forces will deflect your machine, a little and acceptably if the machine is stiff, or unacceptably if not. If it flexes it will vibrate and the cuts will be inaccurate.
It just what happens.

If you want to cut steel then make that choice early and then work towards it, its quite a mission and will result in a different machine altogether than what you have proposed.
Otherwise ditch the idea of cutting steel and proceed accordingly. You ideas, if well executed would be fine for aluminum,brass, wood and plastics,.....but always be poor for steel.

How do I know this?...I tried and failed! I learnt my lesson and have had another go, and much, much better, but still a long way from where I really want to be.

Craig

[peteeng]

Hi Mogi - Looked at the link. Yes topology optimisation is the "old" word for it. It's now called generative design or adaptive design. Seems SW does it via FE and Ansys. This is the slow way to do it as FE meshes take a long time to solve and decimate. F360 and others use meshless algorithms that solve very fast. The generative solutions often are unbuildable but give insight into how it could look unless you 3D print. I don't pay for coupons so don't get the full info out of F360 but enough to get clues to how to go fwd with a new design. Peter

Re steel - There seems to be an idea that you can do something like cut steel "occassionally" with an under-par machine. Sorry this does not work. The machine either will cut or won't cut, if under done it won't cut, it will precess, wobble, stall, vibrate etc etc. I've been thru that with aluminium. If you want to cut steel you really need to look at machines that do what you want and gain an understanding of why they work and how they work. Even the spindle is a different rabbit hole. The spindle suppliers will not say that they can machine steel. They say they can engrave steel. So the lifetime of a "router" spindle will be short. So keep researching, long way to go. The year will pass quickly... Peter

https://youtu.be/6dI8_-fguk0 heres a small router cutting steel and it is like dentistry, so its possible if time is not important...

The other aspect is that Mogi has picked a gantry machine. This is usually because of the size of the parts required to be made. Mogi if you don't need such a big platform make a Bridgeport style machine. This will be easier to make as a mill. A gantry machine has an extra axis, gantry alignment and stiffness issues that need to be overcome to cut steel... I'm not trying to talk you out of it just trying to lay out the hurdles..

I would find an exemplar machine and study it... Peter

[Mogilogi]

Hi Mogi - Looked at the link. Yes topology optimisation is the "old" word for it. It's now called generative design or adaptive design. Seems SW does it via FE and Ansys. This is the slow way to do it as FE meshes take a long time to solve and decimate. F360 and others use meshless algorithms that solve very fast. The generative solutions often are unbuildable but give insight into how it could look. I don't pay for coupons so don't get the full info out of F360 but enough to get clues to how to go fwd with a new design. Peter

Hi peter, Yea i got the point, it helps you identify the weak spots in your design and where can you put support to make it better, can i export from solidworks to F360 to use their Generative design ? or my design should be built in F360?

[peteeng]

Seems my response is lost - Damn
Yes Mogi - topological optimisation is called generative design by many now. SW uses FE via ansys. This means its slow as the FE uses a mesh and then after solution it decimates the mesh and rebuilds etc etc. Newer systems use meshless algorithms which are really fast. Peter

[peteeng]

Hi - I have entered here twice and they are lost?? Peter

[peteeng]

hi seems this is not working - peter

- - - Updated - - -

seems this is not working - peter

[peteeng]

seems to be back on line!! Peter

to build an oven the size you need is ambitious within itself. You need to SR the entire machine in one go, then you need someone with a big mill to finish machine it. We have a forge at out mens shed and its hard enough to get small things to red... Getting a machine up to red, do you have a small power station at home? Lots of research to do yet. Peter

[Mogilogi]

seems to be back on line!! Peter

to build an oven the size you need is ambitious within itself. You need to SR the entire machine in one go, then you need someone with a big mill to finish machine it. We have a forge at out mens shed and its hard enough to get small things to red... Getting a machine up to red, do you have a small power station at home? Lots of research to do yet. Peter

Yea i'm too much ambitious, that is why i'm here trying to slow my self down and get more information from experienced individuals.

[peteeng]

Hi Mogi - Here's a fellow with family built a plywood router to build an aluminium plane. Aluminium you see is no issue, but steel another beast. Also there's no reason a CNC can't be rivetted/bolted together, mine are... most planes are are, even biggest ones.. Peter

Thatcher CX4

[peteeng]

Hi Mogi - I have looked a few of Langmuirs videos and the MR-1 seems to cut steel fine. I suggest you copy it and you'll be fine. I found the spindle info and they use an AC servo with a 1:2.67 belt (my guess). The servo runs at 3000rpm and they step it up so it can run to 8000rpm. You can get servos that run 0-6000rpm so no belts needed.

https://youtu.be/wUvRFBXM3JM

Now you can fabricate steel parts and finish machine without stress relief but its a gamble. If your good with oxy-acetylene I suggest braze welding works well or hard soldering both are good off the torch no TSR needed. So pick your poison and let the fun begin...

They use a leadscrew for the Z which I find interesting, use a ballscrew. Make it a bit stiffer then the MR-1 and it will work out. And do a better job at cable management...Peter

or save up and buy the LR-1 much simpler. I'm sure your going to pay $4500USD plus by the time you get it all together. If I built that basic machine here in OZ ($4500USD = $6700AUD) I would have no change from $6500AUD although the machine would be a little bigger...

[Mogilogi]

Hi Mogi - I have looked a few of Langmuirs videos and the MR-1 seems to cut steel fine. I suggest you copy it and you'll be fine.

Yes that is my plan from the beginning, to copy it and do better at the parts that they skimmed on to keep the price low.

I found the spindle info and they use an AC servo with a 1:2.67 belt (my guess). The servo runs at 3000rpm and they step it up so it can run to 8000rpm. You can get servos that run 0-6000rpm so no belts needed.

I saw it before and thought about something similar.

They use a leadscrew for the Z which I find interesting, use a ballscrew. Make it a bit stiffer then the MR-1 and it will work out. And do a better job at cable management...Peter

Yea i'm going with 20mm ballscrew on all axis, Gantry will be 200mm square, Y rails they are using 25mm thick plate, i will be using about 40mm, the width of the x carriage will be 250mm, z carriage 200mm and spindle plate 200m to make the distance between the linear bearings more to give more stability and so on, still researching.

or save up and buy the LR-1 much simpler. I'm sure your going to pay $4500USD plus by the time you get it all together. If I built that basic machine here in OZ ($4500USD = $6700AUD) I would have no change from $6500AUD although the machine would be a little bigger...

I whish, but since i'm Living in Turkey, i can't buy it from them so i choose the building route, since they provided a full video on the install process, i'm gonna follow it even cut the installing helping plates that you can see in the videos.

[Titaniumboy]

Pete,

Do you have any idea how Langmuir made the MR-1 stiff enough to mill steel? Just by the looks of it you would not think it would be steel capable, but videos don’t lie. Have you taken a run at doing any modeling and FEA to tease apart how they are able to do steel?

Do you have any pictures of the 1:2.67 belt drive? I have a small mill similar to a Tormach and my spindle motor is a 3000 rpm AC servo. My pulley ratio is 1:1.5 so I can only get 4500 rpm at the spindle. I would love to get that pulley ratio higher to obtain higher spindle rpm’s, but was told that I couldn’t go much smaller on the diameter of the spindle pulley.

[peteeng]

Hi TiBoy - I'm guessing the ratio, as in the video the belt is closed up in a casing. Unless its a gearbox but unlikely to be a gearbox. The quote max speed is 8000rpm so maybe its a 5000rpm servo and smaller ratio? They do steel with light cuts. The vids look good but there are machine aspects that are poor. Like they run the ballscrews directly to the motors with no thrust bearing, so motor life is at risk specially if shock loaded. They use a leadscrew for the Z for some reason as well. The machine assembly videos are quite good so you see how they are doing various bits of the machine. I suppose if its in a commercial environment and gets a few 1000 hrs on it the owners will know. It does have some vibration as in one vid you can clearly see the chatter in the finish then it gets cleared in the spring cut...

In regard to the pulley diameter you pick a small pulley that works then get a big pulley to suit. 3:1 is common on various things. So you must have a space problem?

There are heaps of routers cutting steel videos and small hobby mills that confuse me. But they are cutting light and fast. Then you maybe able to cut a few things but it must take its toll on the machine. There are even ShapeOKO cutting steel! But not like real mills. I'll have to give my router a shot at steel... Peter

Some thoughts:
1) Its a small machine with a heavy damp base. Many small machines like this are quite light so can get excited easily
2) The gantry rails are across the gantry diagonals. This makes the bearings as far apart as possible plus, it puts the moment centre through the shear centre of the gantry which is quite good. ie this geometry has the least twisting tendency
3) the saddle is highly webbed across the cars so is very stiff. That's if the real saddle looks like the CAD saddles on their site. I just found a picture of the saddle and it looks like an aluminium casting. very solid.

https://youtu.be/-g4_5-AmjpM

[Titaniumboy]

Hi TiBoy - I'm guessing the ratio, as in the video the belt is closed up in a casing. Unless its a gearbox but unlikely to be a gearbox. The quote max speed is 8000rpm so maybe its a 5000rpm servo and smaller ratio? They do steel with light cuts. The vids look good but there are machine aspects that are poor. Like they run the ballscrews directly to the motors with no thrust bearing, so motor life is at risk specially if shock loaded. They use a leadscrew for the Z for some reason as well. The machine assembly videos are quite good so you see how they are doing various bits of the machine. I suppose if its in a commercial environment and gets a few 1000 hrs on it the owners will know. It does have some vibration as in one vid you can clearly see the chatter in the finish then it gets cleared in the spring cut...

In regard to the pulley diameter you pick a small pulley that works then get a big pulley to suit. 3:1 is common on various things. So you must have a space problem

Thanks for your thoughts on the MR-1 and how it gets away with cutting steel. Doing super-slow baby cuts in steel isn’t really a problem for the home gamer if it means being able to make a part as versus not being able to make a part.

My mill uses 5M HTD pulleys and belt. The motor pulley is 63 teeth (94.7mm flange OD and 24.6mm inside flange width) and the spindle pulley is 38 teeth (64mm flange OD and 17.5mm inside flange width) with a 17mm wide HTD belt. The servo motor is 3000 rpm and 1.2kW.

I was told by Novakon that the spindle pulley couldn’t get any smaller because “the power of the servo motor is significant and to properly transfer the motor torque to the smaller pulley, the diameter and the number of teeth engaging the belt drive is a factor. There is not much room to enlarge the motor pulley and the size of the smaller spindle pulley can’t be reduced for practical reasons. To make the ratio any larger would also limit the maximum size that can be tapped due to loss of available torque delivered to the spindle”.

I would happily trade away some rigid tapping capability for increased rpm.