584,841 active members*
4,443 visitors online*
Register for free
Login
IndustryArena Forum > MetalWorking Machines > Uncategorised MetalWorking Machines > Gantry mill for precise milling of aluminium
Page 3 of 4 1234
Results 41 to 60 of 68
  1. #41
    Join Date
    May 2005
    Posts
    3920

    Re: Gantry mill for precise milling of aluminium

    Quote Originally Posted by NIC 77 View Post
    Thanks for the info!

    I'm thinking about using two small Inner Diameter air cylinders at a max pressure of 80 - 90 PSI. That way I would only need a very small reservoir. I was thinking about a small fire extinguisher bottle or small propane tank mounted to the back of my Z plate. Something very small. The higher the working pressure, the smaller it can be. I don't really care if the top of the stroke force is off by 25lbs from the bottom of the stroke force.

    I just don't know if the cheap EBay pneumatic cylinders will leak at those pressures. They say they will take the pressure, but will they leak, I don't know.

    Gas struts would be the easiest, but they all have damping . Hard to even see a damping spec on an inexpensive gas strut, they usually don't mention it.

    Really awesome machine you have made!
    All air cylinders eventually leak to some degree or another. Your best bet here would be to have an airline ran to you tank to keep it topped off. As you note the air cylinder itself doesn't have to be too big in diameter to effectively counter balance a slide. However you still will have a significant pressure increase in your reservoir as the piston is pushed against the construing air. Here is where a pressure regulator that can handle reverse flow comes in handy.

  2. #42
    Join Date
    Jun 2017
    Posts
    15

    Re: Gantry mill for precise milling of aluminium

    Awsome machine! Just wondering what usb controller you used with Mach3?. Cheers

    Sent from my LG-H870DS using Tapatalk

  3. #43
    Join Date
    Jul 2007
    Posts
    1602

    Re: Gantry mill for precise milling of aluminium

    Outstanding build! I like that you used such a thick cross-section in the gantry.

    Did you weigh the gantry before and after the EG fill?

    bob

  4. #44
    Join Date
    May 2013
    Posts
    70

    Re: Gantry mill for precise milling of aluminium

    Nice, im currently running 2000mm/m^2 acceleration, should be able to go higher with better gearing on Thor.

    Very interested in this NT30 spindle too. This is the closest thing I could find, any idea if this could be 'forced' to work the same way? Is it even the same thing?

    https://www.chronos.ltd.uk/acatalog/info_VRANT30.html

    No ATC on yours, how are the tools held in place?

  5. #45
    Join Date
    Jun 2005
    Posts
    1723

    Re: Gantry mill for precise milling of aluminium

    Absolutely beautiful build, seems to do an amazing job on aluminum. You can certainly be proud of this machine. Very nice job.
    Russ

  6. #46

    Re: Gantry mill for precise milling of aluminium

    I absolutely love this! I found it on youtube, it made my day and I really cant wait to upgrade my machine now!

  7. #47
    Join Date
    Apr 2005
    Posts
    629

    Re: Gantry mill for precise milling of aluminium

    My hat is off to you on this build!!! Watching the video, your machine certainly performs as well or better than some of the industrial machines I have seen over the years. Brilliant job!

    Chris D

  8. #48
    Join Date
    May 2011
    Posts
    790

    Re: Gantry mill for precise milling of aluminium

    Quote Originally Posted by linux_fan View Post
    I was expecting question about why not linuxcnc, as my nickname suggest Im more of a linux user I started using mach for my first build and I found cheap and reliable USB motion control card for it. About ballscrews, you are corrrect. If I had unlimited budget, I would go with 10mm pitch ground ballscrews. I actually already have some rexroth brand new 40mm diameter C3 ground ballscrews with 40mm pitch, but they are for another build, and only ballscrews cost more than this whole machine. But as this motors are "only" 400W" I think 5mm pitch is OK, it is small machine, so I dont need rapids of more than 12M/min, and I also think 17M/min is too fast - 3400rpm. I will run them at max 2400rpm. When you go with Chinese ballscrews, I think it is better to go with 5mm pitch, at least in my case as I dont need very fast rapids, due to force of the ball on screw. 10mm pitch screws will produce twice as much force on the wall of screw, and I wouldnt be surprised to see backlash even faster on 10mm pitch screws.
    The nut on a 10mm pitch Chinese ballscrew is much longer than it is on a 5mm. Not sure how this effects the force on the wall of the screw. Regardless, you are using servos that are capable of higher speeds compared to steppers, and whip doesn't seem to be an issue for you, so I have nothing but praise for you and your design decisions on this build. Truly an awesome build sir. I come back every now and then to look at how you've done some things. Certainly one of the best builds as far as quality and performance go.

    I just have one question for you. Where did you buy your ballscrews? I've been reading some horror stories about Chinese ballscrews, but I also know that some of the Chinese stuff is great quality, you just have to pick the right supplier. Looks like the ones you bought are performing well. What are your opinions?

  9. #49
    Join Date
    Jun 2011
    Posts
    16

    Re: Gantry mill for precise milling of aluminium

    Awesome build! I would love to build something similar to this. How much has the project cost you if you don't mind my asking.

  10. #50
    Join Date
    Jun 2014
    Posts
    30

    Re: Gantry mill for precise milling of aluminium

    Glad you like it. Since I got it in motion, I made a lot of parts for some other machine, and it works great. I have also bought BT30 ATC spindle for this machine, I will post here when I upgrade it. Yes, you are right, quality of Chinese stuff is very different. I am lucky I have a great forwarder there, so he finds good quality for me. Ive attached some pictures, This is woodworking machine I am making for a friend of mine. All of the milled aluminium parts I made on my smaller machine.

  11. #51
    Join Date
    May 2011
    Posts
    790

    Re: Gantry mill for precise milling of aluminium

    You're clearly a CNC genius!

    Is that 4 pneumatic cylinders for the counterbalance? Where is your reservoir, are you routing your tube throughout the entire cable chain?

    I'd be very interested in hearing more about how you are accomplishing the work holding. I am aware that some machines like Biesse do this, I haven't seen it on a DIY build until now, I have been thinking of something similar on my machine where I will have a 4th axis under the table, was thinking removable table, but sliding table supports may be better. That's one thing I haven't finalized.

  12. #52
    Join Date
    Jun 2014
    Posts
    30

    Re: Gantry mill for precise milling of aluminium

    Thank you. Ive made some pictures for you. As you can see, small aluminium "brakes" are mounted on each side of alu profile. When you grab handle and push it down, you will release two pneumatic cilinders that will push into aluminium brakes and hold alu profile. So when cilinders arent pushing, you can move profiles arround.
    On profiles, there will be vacuum pods, 3 pieces on each profile. I will make pictures when Im finished. Should be next week.. About counter balance cylinder, it is one cylinder, you can see it sticking in air, longest one. For air reservoir, I just drilled two holes in cross square profile. One for direct connection with cylinder, and one for input from regulator. Welds are air tight, so there is no leaking. Voume is approx 15L. I use sepperate pressure regulator, and have it constantly connected to this "reservoir", so if there are any small leaks, it constantly fills it up. This sistem works great, and Z ballscrew should last very long, as whole Z axis now practically floats in air. Two double rod cylinders you were looking at are for lifting up and down vacum suction system.


  13. #53
    Join Date
    May 2011
    Posts
    790

    Re: Gantry mill for precise milling of aluminium

    OK, that's just awesome.

    I don't claim to understand all what you've done, but awesome it is.

    So those clamps slide in the T-slot and are hooked up to pneumatic cylinders. I had to look at it a few times, then I understood.

    Is this gantry made from steel? It's painted so I can't tell? Are you going to fill this one with epoxy granite?

    The machine that I'm making is from steel tube, but it bolts together in many places. My Z axis is also a Square steel tube with a 1/2" plate welded into the nose of it that the spindle will flange mount to. This is stronger than a flat plate Z axis, unfortunately because of the flange mount on my spindle, which attaches at the nose of the spindle, the spindle body doesn't add any strength to the Z. The problem I am considering is the steel tube will ring like a bell, I can't fill the tube as the spindle will be in it, so I am thinking about bolting some plastic channels to the outside and filling them with some kind of dampening material.

    Actually, I have even been thinking about gluing some thick HDPE strips to the outside of the tube, simply to change the resonant frequency.

    What are your thoughts on this?

  14. #54
    Join Date
    Mar 2017
    Posts
    926

    Re: Gantry mill for precise milling of aluminium

    Nice build! I wish I would have found this thread before I started my build. Lots of great info and inspiration. I am also building a machine to mill aluminum with a similar footprint and spindle weight.

    I am dealing with a similar balancing issue. I bought a 35lb gas spring to balance a 35lb spindle and to take the weight off the nut on the Z-axis. Now that it arrived, I think I made a mistake. Gas springs seem to increase in force as the stroke increases. I.e. They don't provide even weight balancing as you move the spindle up and down the Z axis. It would only provide 35lb of balancing force at the bottom of the axis and provide zero balancing at the top (when the spring is in it's rest position)...


    I am wondering if a simple balancing weight might do the job better (like the lat pulldown at the gym). This way, if I used a 35lb weight, it would provide 35lb of balancing at any point on the z-axis....


    Please can you explain how your regulated air cylinder solution works in this respect? I can see how a regulator would allow you to maintain consistent pressure going into the cylinder but I don't understand how it would prevent the pressure increasing as the cylinder compresses the air inside on the return stroke?


    Or am I worrying too much about maintaining even balancing pressure / weight?

  15. #55
    Join Date
    May 2011
    Posts
    790

    Re: Gantry mill for precise milling of aluminium

    Quote Originally Posted by Goemon View Post
    I am dealing with a similar balancing issue. I bought a 35lb gas spring to balance a 35lb spindle and to take the weight off the nut on the Z-axis. Now that it arrived, I think I made a mistake. Gas springs seem to increase in force as the stroke increases. I.e. They don't provide even weight balancing as you move the spindle up and down the Z axis. It would only provide 35lb of balancing force at the bottom of the axis and provide zero balancing at the top (when the spring is in it's rest position)...
    There are gas struts, which are sealed units with an internal reservoir. These are the kinds of things you will see on the hatch for your minivan. Is this what you bought? If so, it doesn't have zero at the top. Yes, gas struts do not maintain a constant force for the whole stroke, but it isn't 35 to 0. perhaps 29 to 40. Which would still balance really well except for the dampening aspect that most gas struts have. That's why I chose to go with pneumatic cylinders with a reservoir, commonly referred to as a gas spring by many.

    In reality both things are "springs" that use gas. If what you bought was a pneumatic cylinder and you simply plugged one end, you would have a huge amount of force at the bottom, and zero at the top, if the cylinder could extend all the way to the bottom, which of course it can't, then theoretically you would have infinite force at the bottom and zero at the top. You need to use an air reservoir where P1V1 = P2V2. The larger the pressure and the larger the reservoir, the less force difference you will have at top and bottom of the stroke. The area of the bore, or the area of the bore minus the area of the rod (depending on the pneumatic cylinder's orientation), determines how much force is exerted by the spring for a given pressure. Rodless cylinders are another option for this.

    linux_fan understands how these work better than I do, I am going for a closed system that I only occasionally have to top up (fingers crossed), whereas his is fully regulated.

    Quote Originally Posted by Goemon View Post
    I am wondering if a simple balancing weight might do the job better (like the lat pulldown at the gym). This way, if I used a 35lb weight, it would provide 35lb of balancing at any point on the z-axis....
    That only works on something like a mill where you have a moving XY table and a stationary Z column.

  16. #56
    Join Date
    Apr 2007
    Posts
    1955

    Re: Gantry mill for precise milling of aluminium

    Very nice build.

  17. #57
    Join Date
    Mar 2017
    Posts
    926

    Re: Gantry mill for precise milling of aluminium

    Quote Originally Posted by NIC 77 View Post
    There are gas struts, which are sealed units with an internal reservoir. These are the kinds of things you will see on the hatch for your minivan. Is this what you bought? If so, it doesn't have zero at the top. Yes, gas struts do not maintain a constant force for the whole stroke, but it isn't 35 to 0. perhaps 29 to 40. Which would still balance really well except for the dampening aspect that most gas struts have. That's why I chose to go with pneumatic cylinders with a reservoir, commonly referred to as a gas spring by many.

    In reality both things are "springs" that use gas. If what you bought was a pneumatic cylinder and you simply plugged one end, you would have a huge amount of force at the bottom, and zero at the top, if the cylinder could extend all the way to the bottom, which of course it can't, then theoretically you would have infinite force at the bottom and zero at the top. You need to use an air reservoir where P1V1 = P2V2. The larger the pressure and the larger the reservoir, the less force difference you will have at top and bottom of the stroke. The area of the bore, or the area of the bore minus the area of the rod (depending on the pneumatic cylinder's orientation), determines how much force is exerted by the spring for a given pressure. Rodless cylinders are another option for this.

    linux_fan understands how these work better than I do, I am going for a closed system that I only occasionally have to top up (fingers crossed), whereas his is fully regulated.



    That only works on something like a mill where you have a moving XY table and a stationary Z column.
    The one I bought is a gas strut as you described. I got the LMS one that is used on some of their smaller mills as it had the right level of force for my spindle weight.


    I am less worried about this since my last post though. I realized that I don't really need it to provide a consistent 35lb counter balance everywhere on the axis. I just need it to lift enough weight to prevent it going over the rated weight for my Z axis ball nuts.


    I also just upgraded my Z axis screws and the new double nut holds a lot more than the 25lb limit on my deralin lead screw nuts.


    I can see that it would be harder to design a weighted counter-balance on a moving spindle machine. It's probably not impossible though. You would just need the counter weight mechanism to travel along the axis with the spindle. It would probably look messy and maybe require a different x-axis design so maybe it's just not worth it.


    I would definitely like to avoid using any compressed air products in my build if possible. I use a lot of high pressure air gear for my pre-charged air rifles so I know from experience that they can be a recipe for problems. Valves can leak and any tank or cylinder failures can be very dangerous.

  18. #58
    Join Date
    Jun 2014
    Posts
    30

    Re: Gantry mill for precise milling of aluminium

    You can see how everything works on video now:

  19. #59
    Join Date
    Aug 2015
    Posts
    142

    Re: Gantry mill for precise milling of aluminium

    I am so happy to see such a nice and clean build , i am wondering how u make acurate straight place for rails ?
    Do u machine them or use epoxy fill ?
    Have a good time .

  20. #60
    Join Date
    Jul 2017
    Posts
    18

    Re: Gantry mill for precise milling of aluminium

    Only 3 parts for such a build ?! :-P
    Man this is a master piece I'd want to know everything about

    Envoyé de mon A0001 en utilisant Tapatalk

Page 3 of 4 1234

Similar Threads

  1. Aluminium Gantry Router
    By JermNZ in forum DIY CNC Router Table Machines
    Replies: 67
    Last Post: 03-17-2019, 09:54 PM
  2. Homemade Mini CNC Milling Router Mill DIY X Stage Frame Axis Slide Aluminium
    By doitbymyhand in forum DIY CNC Router Table Machines
    Replies: 0
    Last Post: 05-29-2016, 01:23 PM
  3. Homemade Mini Milling Router Mill DIY X Stage Frame Axis Slide CNC Aluminium
    By doitbymyhand in forum DIY CNC Router Table Machines
    Replies: 0
    Last Post: 05-29-2016, 01:18 PM
  4. Smaller milling machines Bed mill vs plano/fixed gantry mill
    By nilrods in forum Drilling- and Milling Machines
    Replies: 0
    Last Post: 12-17-2015, 10:34 PM
  5. Precise holes for bearing -> what endmill for aluminium?
    By mitis in forum MetalWork Discussion
    Replies: 11
    Last Post: 08-20-2014, 06:39 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •