Hi Luka - A low mounted changer will accumulate swarf. In the video did you see the swarf swirl in when the tool moved across? That will eventually create issues. A high mounted ATC with a swing arm is a good thing.... Peter
Digital Industries, Motion Control, Machine Tool Systems
Hi Luka - A low mounted changer will accumulate swarf. In the video did you see the swarf swirl in when the tool moved across? That will eventually create issues. A high mounted ATC with a swing arm is a good thing.... Peter
Yes i have seen some chips fall into tool changer but still that is small amount and with regular cleaning that should not be problematic.
That type would be most space saving ATC that i can think off. ATC gets quite large with SK40 tool tapper
I would use umbrella style tool changer as that would be easiest to make but i need a lot of space for plate in 650mm diameter to hold 24 tools.
Sadly i cannot make machine any bigger, footprint as of now is maximum available to me, maybe i could squeeze additional 100mm on each side but that is all.
I have thinked about tool changer like this
Attachment 458372
But this also need to be mounted high on top of the machine. My whole top machine is space for moving column so i dont know where to put it without getting in way of column.
Little update as I'm waiting for parts to arrive oversee.
In the meantime not much has happened. With my CAD design and ATC tool changer I have hit hard wall.
For now I did not find solution how to make tool changer that would fit in my cnc machine design without making machine bigger. And that is not good for me as I'm at total size limit.
So I'm looking in alternative designs with some compromises.
I could still use all ordered parts for my first design.
Now I'm working on design like this as alternative.
Bridge - Double column design with moving table in one direction. (I lose fixed table with this design but gain in other areas)
I think that machine like this will have higher rigidity and I could make it smaller with ATC than first design. Not exactly smaller but longer and narrower which would suit my workshop better.
Attachment 460484
Any thoughts, pros and cons with this design over moving column design ?
Did some work on CAD design for double column version.
I think I will go with this design from here on.
I will save quite some material and weight, as of now machine has 2300kg of concrete (all white parts are concrete)
No long overhang on y axis and I have space for tool changer as machine it not so wide.
Attachment 460610Attachment 460612Attachment 460614
I have same plan as before make molds, cast concrete and imbed steel surfaces.
Base is now two part because if I make base from one piece, it will be too heavy to move for machining steel inserts. Like this all parts that I need to machine are under 400kg, which is manageable.
What an ambitious project, keeping my fingers crossed.
Re: Toolholder
I started working on mine now, got any beginner tips? like videos you watched for reference etc.?
Yes, it is quite a project.
I have just received notice that my ship from china is coming to port near me so I will get my electronic, controller and ballscrews in next couple of weeks.
For toolholder I have just watched many, many YouTube videos and also followed some good build logs here on cnczone.
Check build log from stef110, he has build awesome machine with ATC
In the meantime I'm very busy with workshop renovation so the place will be ready for new machine build.
Also my CAD design keeps evolving.
Right now it is looking like this
Attachment 461202Attachment 461204Attachment 461206
Looking great, I like how this is evolving. I used the same style of back plate on the base to add stiffness.
My only concern here is the machining of perpendicular faces on the saddle piece. Seems like the traditional fixed gantry layout is best for the DIY builders as flat plates are easier to machine. But maybe you have a clever strategy, or very accurate granite squares to fixture with?
Oh the other thing is the Z carriage spacing- I've noticed that a lot of the professional machines keep the carriage spacing the same as the max cantilever, so the table-to-carriage distance is the same as carriage-to-carriage distance.
Look at Okuma Genos M460/560
https://images.app.goo.gl/P1puKS35A25Jaxhf8
Rails across bridge on vertical (not horizontal). Easier to machine, less moving mass
7xCNC.com - CNC info for the minilathe (7x10, 7x12, 7x14, 7x16)
Hi Luka - Are you going to use the small screws from the "bottom" of the car? Or are you going to have wings or pockets so you can use the large screws from the "top"? Easy access to the car screws makes life much easier...But does usually make things a bit bigger but that's the better compromise to make....Peter
How about this type of tool changer, mounted in front of your spindle. You wouldn't be loosing any valuable space nor will it collide with the workpiece, it also fits your design.
How are you going to orient the spindle for the toolchange?
By the way, here's a treat so you know where to put the cooling pipes. It's the Swift cartridge.
https://grabcad.com/library/bt40-car...wift-nantong-1
I have servomotor for main spindle so orientation is not problem it has build in function that can stop every time at the same orientationHow are you going to orient the spindle for the toolchange?
Thanks for CAD of spindle
I haven't looked at Milltap tool changers much as this is more of exotic to me. Also i would have to move whole tool changer with z axis. Probably i will go with classic umbrella tool changer on side of column.
Good point ! for now design is to go with smaller M8 screws compared to M10 from top down. Now i can still make changes so i can access screws from top and use bigger bolts. Will look into itAre you going to use the small screws from the "bottom" of the car?
Rails and Cars are in size 30. Hiwin RG series with rollers.
Yes i had design like this but i think that it is much easier to make strong saddle like this with big block. With classic design saddle is usually weak point.Rails across bridge on vertical (not horizontal). Easier to machine, less moving mass
If i will be able to machine perfect squares between horizontal and vertical cars - i highly doubt that but i'm thinking to compensate for misalignment with tilting front and back whole column .
Also i'm still working on z carriages spacing as i will try to move them farther apart, but probably i will have to sacrifice some of Z working height (right now at 500mm ) otherwise machine will be over may max 2350mm height with z axis.
Damn, after an extensive session of toolholder modelling, mechanically it's somewhat doable, but Z travel has to take into account the longest tool you're gonna use, so it doesn't crash into the workpiece. It's one of those options/decisions I didn't think existed/had to be made.
Side by side design comparison
Which one would you guys pick
Attachment 461316Attachment 461318Attachment 461320
On right side I have made beefy 120mm cast saddle just for fun
Also Z axis is now 1000mm long spacing of z axis carriages is 500mm so that should do it
Morning Luka - The RHS one having the larger gantry will be stiffer. In the modelling of all sorts of saddles I have done, the saddle itself has been insignificant to the machine stiffness. To correctly choose you need to run it in FEA and see what works best, then you also have to consider assembly logic and manufacturing logic... Not always a clear cut decision. Peter
Initially I thought of using a rotary ballspline for the atc gripper. But to move it up and down I'd need a linear actuator like an air cylinder(I want to avoid using pneumatic stuff) or an electric linear actuator which already use a motor and a screw, so I'd be doubling on components and price and complexity. So to simplify the assembly I'm thinking of using a ballscrew spline in this type of system:
https://www.youtube.com/watch?v=WudGOKXDV6A
It's pricey... hoping I'll get it either used or something similar from TBI motion intead.
You're gonna like this. ATC mounted under the bridge. Simple and space saving.
https://www.youtube.com/watch?v=8DbwIH9qMjA