Australia CNC Plasma purchase advice? - Page 2


Page 2 of 2 FirstFirst 12
Results 21 to 29 of 29

Thread: CNC Plasma purchase advice?

  1. #21
    Member
    Join Date
    Jul 2009
    Location
    Australia
    Posts
    146
    Downloads
    4
    Uploads
    0

    Default Re: CNC Plasma purchase advice?

    Quote Originally Posted by rodw View Post
    if you have one of their machines cutting 30mm plate in a shipyard all day.
    HAHA, that is so funny!



  2. #22
    Member AndrewRead's Avatar
    Join Date
    Aug 2021
    Posts
    8
    Downloads
    0
    Uploads
    0

    Default Re: CNC Plasma purchase advice?

    Thanks Rod,
    Thanks for the offer of having a look at your plasma table but Im in Perth so cant take you up on that. I am leaning towards the weldclass cutforce t2400 setup (American made table with hypertherm plasma). Can I ask if you think it is critical to have an refrigerated air dryer as part of the set up? My compressor will be very close to the plasma. I have read many mixed reviews regarding this one. Some say a good filter will do the job, some say absolutely essential to have a refrigerated air dryer??



  3. #23
    Member
    Join Date
    Jul 2009
    Location
    Australia
    Posts
    146
    Downloads
    4
    Uploads
    0

    Default Re: CNC Plasma purchase advice?

    Andrew,

    I run a refrigerated air dryer as part of all my setup as well as the Sharpe 6760 Desiccant dryer systerms. In 2000 I started out with a Plasmacam 4 x 4 with a 1650 Hypertherm, then I sold it and built a 3000 x 1500 table with Candcnc electronic it had a 105 Powermax I have since sold it. I have also built a 3500 x 2000 for a guy it had a SZGH system on it and it ran a 125 Powermax. Nowadays I use a 7500 x 2200 with a 105 Powermax and I wish I had kept my 3000 x 1500 table with Candcnc electronic it was a good machine.



  4. #24
    Member
    Join Date
    Nov 2013
    Posts
    1392
    Downloads
    0
    Uploads
    0

    Default Re: CNC Plasma purchase advice?

    Hi,
    here in New Zealand it's the exception rather than the rule to have an air dryer.....filters yes...dryers no.

    It comes down to humidity and consequently the water vapor content of the compressed air. Water vapor causes accelerated consumable wear. If you use
    your table sparingly then you'll probably never recoup the extra money for an air dryer, whereas if you operate in humid conditions and high duty use then an
    air dryer will pay for itself many times over.

    Craig



  5. #25

    Join Date
    Sep 2021
    Posts
    1
    Downloads
    0
    Uploads
    0

    Default Re: CNC Plasma purchase advice?

    Looking for the best plasma cutter under 1000? Well, it's not that easy to search that with the budget constraint; however, my reviews will help you.



  6. #26
    Member AndrewRead's Avatar
    Join Date
    Aug 2021
    Posts
    8
    Downloads
    0
    Uploads
    0

    Default Re: CNC Plasma purchase advice?

    I've ordered my table and getting excited. Have started playing around with inkscape getting ready for my first projects when table arrives. I was wondering what is the thinnest cut you can achieve without blowouts or other issues? By this I mean the positive space (metal) left between two cuts ie if you cut a rectangle (LxW) shape what is the smallest width you can get away with ? Would 5mm be enough?
    I will mainly be cutting 3mm aluminum and 1.6mm steel.
    Also, is there a way to get a notification to your email address when someone has posted on this thread?
    Thanks guys!



  7. #27
    Member
    Join Date
    Nov 2013
    Posts
    1392
    Downloads
    0
    Uploads
    0

    Default Re: CNC Plasma purchase advice?

    Hi,
    the smallest feature will be determined by the minimum kerf width.....and kerf width is governed by many factors, some of which are under your control.

    I would suggest that you use Hypertherm's FineCut consumables, they will almost certainly result in the best cut and smallest kerf with thin materials.

    The best cut, with respect to generation of dross, squareness of the kerf and minimum width kerf occur when the arc is 'attached' to the work piece at out 2/3 to 3/4
    of the material thickness. So for 1.6mm steel you'd want the arc point to be about 1mm below the surface of the material. To maintain that depth at a given current,
    and the current is usually determined by the 'sweet spot' of the consumables in use, requires a definite cut speed.

    Lets say for example your consumables operate optimally at 35A. Then in 1.6mm material you might find to maintain 1mm arc depth you will have to cut at 6m/min.
    If your machine is limited to 5m/min then the arc depth will increase, maybe even completely penetrating the material, with loss of cut quality. Alternately you might
    try cutting at 7m/min and find that the arc depth is only 0.5mm rather than your target 1mm. This will result in reduced cut quality as the plasma ejected materail
    will tend to 'blow back' to the torch.

    To a large degree the arc voltage will determine the height of the torch above the material and in combination with the speed of cut will determine the arc penetration.
    The ability of your machine to maintain that arc depth constant will depend to a large degree on your torch height control mechanism but also VERY strongly on the ability
    of your machine to accelerate quickly to your target cut speed. For instance, if you come to a 90 degree corner the machine will decelerate to near standstill before accelerating
    away in the new direction. While the machine is decelerating then accelerating it will be at less than optimum speed and the only recourse is for the torch height control
    to maintain arc depth as close as possible to optimum.

    Usually the acceleration ability of your table is determined by axis mass, the servos used and the drive system. In any event its common to tune the machine to its maximum usable
    acceleration and leave it there. Its not typically under your control. What is under your control is the properties of the torch height controller and the anti-dive strategies you use.
    These will give you many hours of experimentation before you arrive at the best compromise.

    I would guess that if your machine is fast enough and the torch height controller has good bandwidth and tuning features the 5mm features will be possible in 1.6mm steel,
    maybe a little more in 3mm aluminum. The cut heat will tend to cause the minimum width section to distort upwards towards the torch or downwards away from the torch,
    placing high demand on the torch height controller.

    I worked extensively with a customer whom had a large and capable machine with a 200A Hypertherm plasma. We obtained very good cut quality with feature sizes approaching
    5mm at speeds of 8-10m/min at 100A in 3mm steel, the customers goto thickness material. The controller on this machine was a Chinese made thing, it worked but was
    unreliable. I convinced the customer to go to Mach4 and a Vital Systems Hicon controller with a Proma torch height module, which at that time was the leading combination
    available with Mach4 software. It proved (and still is) to be a great success.

    Were I to revisit the problem I would go for Mach4, an Ethernet SmoothStepper and TMC3in1 torch height controller. The ESS offers realtime THC that it did not some five
    years ago and the TMC troch height control has some sophisticated anti-dive strategies that offer tuning possibilites that did not exist back then.

    Craig



  8. #28
    Member AndrewRead's Avatar
    Join Date
    Aug 2021
    Posts
    8
    Downloads
    0
    Uploads
    0

    Default Re: CNC Plasma purchase advice?

    Wow! Thanks Craig, that's a very comprehensive reply.

    I've got a lot to learn. Looks like I will be sacrificing quite a few sheets of metal just to work everything out.!

    I think I've mostly worked out Inkscape basics for cnc plasma now. The machine comes with Sheetcam and Mach 3 so will need to play around with these once the machine arrives to work it all out.

    Any advice on initial set of cuts? Should I just do some very basic shapes to enable me to work out what settings to use/change?



  9. #29
    Member
    Join Date
    Nov 2013
    Posts
    1392
    Downloads
    0
    Uploads
    0

    Default Re: CNC Plasma purchase advice?

    Hi,
    I would suggest that your experiments be directed in a series of goals....and don't try goal three when you've still to master goals 1 and 2.

    I would suggest a series of simple straight line cuts, say 300mm long so that you have ample oppurtunity to observe the kerf at full target speed.
    Parallel cuts say 1-2 cms apart to start with. You should experiment with current settings of the plasma guided by Hypertherm's manual,
    the arc voltage setting of your torch height controller and cut speed, G1 Fnnn in Gcode. You are looking for the cleanest, fastest cut with
    square kerf.

    Then I would experiment with line segments in a polygon, say a hex sided polygon. Again you want to be able to hit target speed during each line segment,
    so depending on machine acceleration maybe 100mm long. You want to experiment and observe the kerf as the machine decelerates and then accelerates
    away from each angle change. Tune your torch height and anti-dive settings and the CV settings in Mach to achieve the best kerf at speeds less than target speed.

    I should think that will keep you busy for a while.

    Piercing is another operation that needs experimentation. Passing over a previously cut kerf is another....any machine that can handle that well is likely
    to be a flexible and capable machine and should be attempted. Another area that requires experimentation is cutting holes, bolt holes etc.
    Hypertherm have a special software package called 'TrueHole' or some such and is designed to produce the best possible holes in material......and they
    CHARGE you for it BIGTIME. Cutting good boltholes is a real feather in your cap.

    Craig



  10. #30
    Member AndrewRead's Avatar
    Join Date
    Aug 2021
    Posts
    8
    Downloads
    0
    Uploads
    0

    Default Re: CNC Plasma purchase advice?

    Thanks again Craig. I'm guessing I would need to do this each time for the mild steel, stainless steel and aluminium I am planning on cutting to work out optimal settings for each material?
    Slim chance I'm sure, but you wouldn't happen to be from Perth, WA at all would you?



Page 2 of 2 FirstFirst 12

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

CNC Plasma purchase advice?

CNC Plasma purchase advice?

CNC Plasma purchase advice?