Newbie Homemade CNC with Scrap + Chinese parts || Objective: Milling Aluminium ||


Results 1 to 19 of 19

Thread: Homemade CNC with Scrap + Chinese parts || Objective: Milling Aluminium ||

  1. #1
    Registered
    Join Date
    Jul 2016
    Location
    Portugal
    Posts
    12
    Downloads
    0
    Uploads
    0

    Default Homemade CNC with Scrap + Chinese parts || Objective: Milling Aluminium ||

    Hello guys,
    I already had build a 3D printer in 2013, I started to get bored with it, so I start to see some CNC videos on internet about CNC routers and I thanked: I can do it!!!

    So I made a little research about homemade CNC's and I find out that I will need:
    -Control system
    -Stepper motors + drivers
    -Transmission (belt's + pulley's)
    -Ballscrews
    -Linear rail/rods
    -Metallic structure
    -Spend little money as possible

    So after that I went to my backyard and I found some 50*50mm steel tubes, perfect for the structure!
    I went to the scrapyard and I found some aluminium tables with 15mm linear rails that looked perfect for X&Y axis and a linear structure with 20mm rod's that was good enough for Z axis.

    I searched on ebay and found Nema 23 with 270oz-in with TB6560 driver + 24V power supply and mach 3 interface for a reasonable price.
    The belt's and pulley's were ordered from www.bepltd.com, very nice guys, aluminium pulleys with 20&40 teeth for 1:2 ratio and HTD 3M belts, perfect for very small or no backlash.

    After some time I found out my computer was not able to connect to Mach 3 interface via LPT1... So was time to search for USB solutions, and i found GRBL.
    After that I ordered a One CNC V3 and an Arduino Uno from Ebay, perfect for the job.

    After lots of welding, drilling, tappering, ect the cnc was running perfectly, almost squared!!!

    At that time I explored the limits of the machine, and i find out that I abused with microsteps. The machine was too precise, too slow and with almost no torque.
    Time to do some research:
    -Calculation torque Vs microsteps & step/mm to achive resolution Excel link


    With this excel I understand why we should not abuse of microstepping, and why is important to choose a pretended resolution to you CNC machine.
    An important factor is also driver voltage, TB6560 only are able to have a input voltage of 30V, this is a limitation to achieve max torque at higher stepper motor speed.

    Spindle was a a very difficult choose since I don't really know what the machine can handle, so i went for 0.8kW+VFD chinese spindle water cooled from ebay, now I'm a bit regretted due collect 11 isto small(max 7mm mills).

    Material:
    CNC Structure & Parts
    Steel tubes: Backyard
    Aluminium parts: Bought on junkyard
    Fixation: Welded steel tubes & screws

    Linear rails: Came toghether with aluminium plates
    Linear rails X&Y axis: 15mm wide
    Linear rod Z axis: 20mm

    Stepper motors: Nema 23 76mm 270oz-in (1.6N-m)
    Driver: TB6560 + 24Vpower source
    Control: One CNC V3 + arduino Uno + GRBL

    Ballscrews: 1605 (Ø16mm & 5mm/rot)

    Belts & Pulleys:
    Ratio: 1:2 (20x40 teeth)
    Belt: HTD 3M 9mm wide

    Spindle & VFD
    Power: 800W
    RPM: 24000
    Collet: ER11 (max 7mm)
    Water cooled



    So enough of talk and lets see the machine working!!




    Next steps:
    -Mill Aluminium Spindle brackets
    -Make a box for CNC (maybe soundproof)
    -Protect rails and ballscrews from chips.


    I know this is not a perfect CNC, but for the first one I'm proud of it!

    If you have any idea or improvement please share, Thanks.


    Similar Threads:
    Attached Thumbnails Attached Thumbnails Homemade CNC with Scrap + Chinese parts  || Objective:  Milling Aluminium ||-img_20170914_185354_hdr-jpg   Homemade CNC with Scrap + Chinese parts  || Objective:  Milling Aluminium ||-img_20170914_185308_hdr-jpg  
    Last edited by Laranjas3; 09-29-2017 at 06:55 AM.


  2. #2
    Member handlewanker's Avatar
    Join Date
    Sep 2006
    Location
    Australia
    Posts
    6463
    Downloads
    0
    Uploads
    0

    Default Re: Homemade CNC with Scrap + Chinese parts || Objective: Milling Aluminium ||

    Oh....a mill....I was wondering what it actually was before seeing the photo blown up bigger.

    I think you've done a marvelous job under the circumstances.......backyard engineering using the utmost ingenuity is the very essence of inventiveness.

    I have deep respect for anyone who can apply logic and put parts together to make them work despite many setbacks and re-visions of the build as it goes along......the end justifies the means in all case without exception.

    One thing I think you will find a bother.......the spindle is only really suited for high speed carving work as the limited torque at low revs (for steel milling) could damage the VFD as it has to pile on the amps to put out the torque.

    That would be the only area I would revise if you intend to do milling work......it is a mill after all not a CNC router that is more suited to a high speed spindle.

    In that, I would consider a separate spindle and bearing set-up with a belt drive motor....possibly a 3 phase 1 HP type with a VFD to get the low rpm speed range and low down torque........VFD's can work on single phase electric supply and put out variable 3 phase to drive any 3 phase motor.......I have such a set-up on my small lathe....1/3 HP capacity.
    Ian.



  3. #3
    Registered
    Join Date
    Jul 2016
    Location
    Portugal
    Posts
    12
    Downloads
    0
    Uploads
    0

    Default Re: Homemade CNC with Scrap + Chinese parts || Objective: Milling Aluminium ||

    Thank you for the comment, I tried to not spend too much money on it.
    The spindle for sure was the thing that I questioned my self if it was a good option, and at that time I thinked for start it was enought.

    Your suggestion to use a spindle and a external 1HP motor is very good, and for sure it will be one of the upgrades that I will do in the future!

    Right now I will focus on finishing the end limits and improve the containing of flying chips!

    Thank you.



  4. #4
    Member
    Join Date
    Jun 2011
    Location
    US
    Posts
    692
    Downloads
    0
    Uploads
    0

    Default Re: Homemade CNC with Scrap + Chinese parts || Objective: Milling Aluminium ||

    Biggest improvement you could make from looking at that cut you're doing is choke up on that endmill. Don't leave any of the shank out of the holder if you don't need to for your maximum depth of cut. Also, carbide tooling is stiffer than steel, and well suited to high-speed spindles. 750ish SFM (~240m/min) is a bit fast for HSS in aluminum I think. It's about the starting point for carbide though.
    50% stepover is often considered an area to be avoided. Not sure how true it is, but I've heard that when the flutes of your tool are hitting the edge of the piece perpendicularly (as they will with 50% stepover,) it's the worst case for them. Better to stay below 40% or above 60%. With lighter weight linear bearing machines, generally it's best to stick to 1/5 to 1/3 stepover and higher feeds.
    Speaking of higher feeds, you're only at .002mm feed per tooth. It's best to try and keep that above around .02mm, so 1000mm/min at 12000 RPM. If it's too much for the spindle or the stiffness of the machine, reduce the cut depth if you have to.
    Also, 4-flute mills are generally not good for aluminum. 2 and 3 flute are generally preferred. 2 flute are cheap, but there are quite a few aluminum specific 3-flute mills that can do a better job because of their geometry. Fewer flutes helps with the feed per tooth as well. A 2 flute end mill would only have to travel 500mm/min to be cutting at .02mm per tooth. If you end up looking at endmills with coatings, avoid AlTiN or TiAlN coated for aluminum. The aluminum in the coating is rumored to make them more likely for the Al you're cutting to stick to the mill and load up the cutter (usually leading to a broken endmill and ruined part.) Uncoated are fine for aluminum, ZrN, CrN, TiCN and DLC are good coatings for aluminum, but tend to be more expensive. TiN and other coatings generally don't help much, but are usually fine if you find some for cheap. Uncoated is usually the cheapest though, and work fine, so generally the best to stick with while you're still experimenting with the machine and more likely to break them (better to break a cheap bit than an expensive one..)

    The machine itself looks pretty good for what you managed to scrounge together. I don't think going with the high-speed spindle was a mistake if aluminum and wood are primarily what you want to use it for. Steel milling is never going to work well, but the rigidity of the machine will likely be a problem if you had a spindle with more torque. Decent belt driven spindles that can handle 1+ HP generally aren't that cheap, and typically the induction motors you would drive with a VFD are quite heavy. I think I would go for a beefier high speed spindle (2.2kW typically take an ER20 collet,) before going for a belt driven spindle.



  5. #5
    Member handlewanker's Avatar
    Join Date
    Sep 2006
    Location
    Australia
    Posts
    6463
    Downloads
    0
    Uploads
    0

    Default Re: Homemade CNC with Scrap + Chinese parts || Objective: Milling Aluminium ||

    Hi, any and all high speed spindles suffer from low speed torque reduction.....that is in the 6,000 rpm range, so steel cutting even with a 6mm diam cutter is still too fast and with no power to get into the cut.......the spindle will dramatically slow down and the amps will increase until the VFD gives up.......that is costly.

    You could use shallow depth of cuts and more of them to prevent the cutter from overloading the spindle.....it just takes a bit more time, but you'll get there as it's a CNC and you don't want to stand and watch it like a manual mill.

    At least you have a CNC mill even if it takes a bit more time.

    A CNC program runs by itself from beginning to end and you only get the finished part when the spindle stops.......a few more minutes won't make any difference.
    Ian.



  6. #6
    Registered
    Join Date
    Jul 2016
    Location
    Portugal
    Posts
    12
    Downloads
    0
    Uploads
    0

    Default Re: Homemade CNC with Scrap + Chinese parts || Objective: Milling Aluminium ||

    Hi, thank you for the explanations.
    For sure I need to learn about speeds and feeds.
    Right now I think I only have 4 flute mills, but I will take that in consideration!

    Now I'm doing the brackets for this spindle to improve rigidity. After that I will try to do the first "CNC" all by it self part!

    Enviado de meu Redmi Note 4 usando Tapatalk



  7. #7
    Member
    Join Date
    Jun 2011
    Location
    US
    Posts
    692
    Downloads
    0
    Uploads
    0

    Default Re: Homemade CNC with Scrap + Chinese parts || Objective: Milling Aluminium ||

    Minimizing the stickout is probably the biggest thing, but yes, fewer flutes are better when you don't have a lot of torque.



  8. #8
    Registered
    Join Date
    Jul 2016
    Location
    Portugal
    Posts
    12
    Downloads
    0
    Uploads
    0

    Lightbulb Re: Homemade CNC with Scrap + Chinese parts || Objective: Milling Aluminium ||

    Hello guys,
    So I'm doing 2 Aluminium brackets for my 0.8kw spindle.



    I could do it by milling an aluminum plate, but long time ago I want to make a full video of lost PLA on plaster mold for aluminium casting.


    So how I will document this:
    Part 1:
    -Fusion 360 modeling
    -Slic3r Gcode generating
    -3D printing
    -PLA welding with soldering iron


    Part 2:
    -Make of plaster mold
    -Dry of the mold & melt of PLA
    -Aluminium casting


    Part 3:
    -Fusion 360 CAM
    -Mill the aluminium bracket to the spec




    Here you have the first video (Part 1/3):





    Any idea os suggestion?


    Thank you

    Attached Thumbnails Attached Thumbnails Homemade CNC with Scrap + Chinese parts  || Objective:  Milling Aluminium ||-motor-bracket-jpg  


  9. #9
    Registered
    Join Date
    Jul 2016
    Location
    Portugal
    Posts
    12
    Downloads
    0
    Uploads
    0

    Default Re: Homemade CNC with Scrap + Chinese parts || Objective: Milling Aluminium ||

    Hello guys,
    Today I completed the part 2 of the video, the plaster mold preparation and aluminium casting.








    I hope you enjoy.


    Thank you

    Attached Thumbnails Attached Thumbnails Homemade CNC with Scrap + Chinese parts  || Objective:  Milling Aluminium ||-img_20171025_190642-jpg  


  10. #10
    Member
    Join Date
    Dec 2006
    Location
    usa
    Posts
    51
    Downloads
    0
    Uploads
    0

    Default Re: Homemade CNC with Scrap + Chinese parts || Objective: Milling Aluminium ||

    Nice video! Those turned out great!



  11. #11
    Registered
    Join Date
    Jul 2016
    Location
    Portugal
    Posts
    12
    Downloads
    0
    Uploads
    0

    Default Re: Homemade CNC with Scrap + Chinese parts || Objective: Milling Aluminium ||

    Thanks for the comment!

    I tried to mill the parts yesterday with some drawbacks:
    -Too much RPM & worn out tool
    -New tool with 12k rpm milled the aluminium with goos quality
    -M30 at the end of Gcode that broke my carbide tool -_-

    The CNC broke the mill with lots of class!

    Check the video:


    Thank you guys.



  12. #12
    Registered
    Join Date
    Jul 2016
    Location
    Portugal
    Posts
    12
    Downloads
    0
    Uploads
    0

    Default Re: Homemade CNC with Scrap + Chinese parts || Objective: Milling Aluminium ||

    Hello guys,
    Finally I used the CNC to mill the spindle brackets, I hope you enjoy:






  13. #13
    Member
    Join Date
    Mar 2017
    Location
    United States
    Posts
    926
    Downloads
    0
    Uploads
    0

    Default Re: Homemade CNC with Scrap + Chinese parts || Objective: Milling Aluminium ||

    Quote Originally Posted by handlewanker View Post
    Hi, any and all high speed spindles suffer from low speed torque reduction.....that is in the 6,000 rpm range, so steel cutting even with a 6mm diam cutter is still too fast and with no power to get into the cut.......the spindle will dramatically slow down and the amps will increase until the VFD gives up.......that is costly.

    You could use shallow depth of cuts and more of them to prevent the cutter from overloading the spindle.....it just takes a bit more time, but you'll get there as it's a CNC and you don't want to stand and watch it like a manual mill.

    At least you have a CNC mill even if it takes a bit more time.

    A CNC program runs by itself from beginning to end and you only get the finished part when the spindle stops.......a few more minutes won't make any difference.
    Ian.

    Most spindles have consistent torque up to their rated speed and reduced torque at their highest speed. It's just that smaller high speed spindles have low torque period. They certainly don't have any more torque at 16,000rpm than they do at 8,000rpm unless they are constant power (which is rare).

    In general, you need more power to maintain torque for higher speed spindles. A 6000rpm 2.2kw spindle might have 3-4 times more torque than a 24,000rpm 2.2kw spindle. But, there are plenty of high speed spindles with lots of low speed torque. The Hass mini mills, for example, have 30,000 RPM 20kw+ direct drive spindles with plenty of low speed torque. Most of us can't afford them though.

    The other thing is that cheaper spindles with shaft fans have cooling that is proportionate to speed. In other words, they don't get sufficient cooling at low speeds so they are not rated for use at less tha but 10,000 rpm or sometimes 8,000.



  14. #14
    Registered
    Join Date
    Jul 2016
    Location
    Portugal
    Posts
    12
    Downloads
    0
    Uploads
    0

    Default Re: Homemade CNC with Scrap + Chinese parts || Objective: Milling Aluminium ||

    Thank you for the useful information!
    Right now I'm using a water cooled Chinese spindle, do you have idea what is the minimum speed that I can use?

    Thanks.



  15. #15
    Member
    Join Date
    Jun 2011
    Location
    US
    Posts
    692
    Downloads
    0
    Uploads
    0

    Default Re: Homemade CNC with Scrap + Chinese parts || Objective: Milling Aluminium ||

    Quote Originally Posted by Laranjas3 View Post
    Thank you for the useful information!
    Right now I'm using a water cooled Chinese spindle, do you have idea what is the minimum speed that I can use?

    Thanks.
    Seems like down to 6000 RPM tends to be pretty easy, but below that you need to get the settings just right in the VFD to avoid torque drop off. Keep in mind that you'll only have 200W of power at best at 6000 RPM and it will continue to drop below there, so even if you can keep the torque flat, you may not have enough power to do anything useful at lower RPM's.



  16. #16
    Member
    Join Date
    Jun 2011
    Location
    US
    Posts
    692
    Downloads
    0
    Uploads
    0

    Default Re: Homemade CNC with Scrap + Chinese parts || Objective: Milling Aluminium ||

    Quote Originally Posted by Goemon View Post
    Most spindles have consistent torque up to their rated speed and reduced torque at their highest speed. It's just that smaller high speed spindles have low torque period. They certainly don't have any more torque at 16,000rpm than they do at 8,000rpm unless they are constant power (which is rare).
    A constant power spindle would have double the torque at 8000 RPM than at 16,000, not the other way round.



  17. #17
    Registered
    Join Date
    Dec 2008
    Location
    egypt
    Posts
    21
    Downloads
    0
    Uploads
    0

    Default Re: Homemade CNC with Scrap + Chinese parts || Objective: Milling Aluminium ||

    Thank you for the useful information!

    Check out our selection of free-to-use DXF,STL,SVG,CDR files, with new downloads added every day https://www.cncworld.tk


  18. #18
    Member
    Join Date
    Mar 2017
    Location
    United States
    Posts
    926
    Downloads
    0
    Uploads
    0

    Default Re: Homemade CNC with Scrap + Chinese parts || Objective: Milling Aluminium ||

    Quote Originally Posted by skrubol View Post
    A constant power spindle would have double the torque at 8000 RPM than at 16,000, not the other way round.
    Which is why I specifically said "unless it's a constant power spindle" which it isn't in this case. Almost all of the spindles people use here are not constant power.

    Most spindles increase in power as rpm goes up to maintain constant torque until their rated speed when torque drops off. Torque will drop off at top speed even on a constant power spindle though. No spindles have more torque at max speed than low speed. Just take a look at any torque /speed / power chart.



  19. #19
    Member
    Join Date
    Mar 2017
    Location
    United States
    Posts
    926
    Downloads
    0
    Uploads
    0

    Default Re: Homemade CNC with Scrap + Chinese parts || Objective: Milling Aluminium ||

    Quote Originally Posted by Laranjas3 View Post
    Thank you for the useful information!
    Right now I'm using a water cooled Chinese spindle, do you have idea what is the minimum speed that I can use?

    Thanks.
    Most manufacturers state the rated speed range but it's based on cooling. A water cooled spindle should do better at low speeds than cheap air cooled units with shaft fans. Check the manufacturers specs



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
  •  


About CNCzone.com

    We are the largest and most active discussion forum for manufacturing industry. The site is 100% free to join and use, so join today!

Follow us on


Our Brands

Homemade CNC with Scrap + Chinese parts  || Objective:  Milling Aluminium ||

Homemade CNC with Scrap + Chinese parts  || Objective:  Milling Aluminium ||