Which THC is suitable for Hypertherm HyPerformance HPR260?

[sunmix]

Hello friends,

I will be purhcasing a Hypertherm HyPerformance HPR260. I want to have a reliable but affordable torch height system. I will not use Hypertherm's CommandTHC, it kills my budget. Any suggestions?

sunmix

[jimcolt]

The HPR260 is a high definition class plasma.....it must be used with a THC that can maintain arc voltage to +-1 arc volt. The THC also must have Ohmic plate contact as a backup for initial height sensing...initial height sensing should have "stall" or "torque" sensing of the plate that is adjustable.

Other features that are part of the height control that will make the HPR260 more productive...Preflow during IHS, Kerf crossing detection, Ohmic collision detection, crash sensor.

There are only a few THC systems that are adequate for this type of plasma.. The Hypertherm Command and Sensor THC systems as well as the Kaliburn Innova THC.

If you are buying a new cutting machine...many of the cutting machine builders have integrated THC systems that are designed to work with high definition plasma systems.

The HPR260 is a high frequency start, 100% duty cycle, liquid cooled, 2" diameter industrial plasma torch. It can cut and mark from 7 Amps to 260 amps....with a thickness range from 28 gauge to 2-1/2".....piercing capability is to 1-3/8".

Jim Colt

[sunmix]

How does Ohmic plate contact works? What is initial height sensing?

[jimcolt]

Ohmic contact is the sensing of contact between the torch shield (front part of the torch) and the plate. This is used to accurately determine where the top of the plate is when cutting above water or on materials that are not primed, masked or do not have a lot of rust or scale. The Ohmic contact function (on some THC systems) is also monitored by the THC during cutting in the event that the torch touches the plate...or a piece of slag on the top of the plate..if contact is sensed then the torch rapidly rises to avoid the collision.

IHS (initial height sensing) is extremely critical with all mechanized plasma cutting applications.....this is the sensing of the location of the top surface of the plate (before the torch fires)...then retracting very accurately to the pierce height (which is usually 1.5 to 2 times the optimal cut height). IHS is achieved using ohmic contact with the plate (if the top if the plate is electrically conductive...rust, water, primer, masking will affect this process)....or by stall or torque sensing (z axis drive motor).

One pierce too close to the plate can damage a plasma nozzle...so IHS is very critical if you expect the best performance from your plasma.

Jim

[sunmix]

Hi Jim, thanks for the detailed answer!

Does Campbell THC, DynaTorch THC, CandCNC THC, or Torchmate THC available for these powerful features?

[jimcolt]

You should check with them to see if they can support the HPR260 plasma torch with their THC systems. What cutting machine will you be using with the HPR260?

Jim

[sunmix]

Hi Jim,

I've asked all of them and I find CampbellTHC is the most suitable, because they seem to work for HPR260. I am actually building my own CNC.

[jimcolt]

I was not aware that the Campbell THC had the Ohmic contact function....or that it could handle a high frequency start torch that is as heavy as the HPR260....if it has this capability that is great!

A couple of notes:

- The HPR260 is the best you can buy in the world of plasma cutting. It is an expensive unit that requires excellent x-y and z motion control in order to realize its full capabilities in terms of cut quality, cut part accuracy and consumable life.

-Z axis (THC) control is probably the single most important factor that affects hole quality, fine feature quality as well as life of the consumable parts in the torch.

-The THC can help the cutting machine/plasma torch become far more productive and trouble free if it is 1. Fast (excellent retract speed, excellent IHS speed to reduce cycle times between cuts), 2. Has preflow during IHS (The HPR plasma has a 1.4 second gas preflow before each cut cycle)....if the THC has the ability to start this preflow while it is indexing toward the plate to establish the pierce height...then it can be a real cycle time reducer.

- The HPR torch body is stainles steel, 2 inches in diameter and is liquid cooled...with a rather large leads package attached to it. make sure the z axis can handle the weight of this unit!

-The HPR torch uses high frequency (approx 15,000 volts @ 1.2 mhz) to ionize the plasma gas...this creates electrical noise during each start cycle that can affect THC system electronics as well as the cnc control electronics. Many of the entry level or hobby class THC's and CNC's are designed for use with non-high frequency start plasma systems. Ensure that your electronics are adequately hardened to operate with this type of industrial plasma torch!

Good luck with your plasma table build!

Jim Colt

[sunmix]

Teehee!

I don't think it has a Ohmic Contact Feature, but he did say this:

" It looks the voltage is in range. I have not found if the HF is on all the time or just when peircing. It generates more noise while the HF is on. It does have a nice feature of being able to reduce the current during sharp turns when the X Y speeds slow down. Mach has an output for that that could easily drive a relay to energize that feature."

and this:

"I don't see any reason why it would not work. I see a place to fire the torch,
monitor Arc Transfer
monitor tip volts.
The explain well the noise issue and how to tackle it."

I did ask him if the THC as ohmic contact feature, and I am waiting for his reply. Meanwhile, I have emailed Kaliburn for a price quote.

I will be using a DD motor for my longtitude travel, and 2 300 watt bldc servos for traverse and Z axis.

Is that ok?

[jimcolt]

I don't consider myself a drive expert....so I can not offer you good advice for designing the z axis motor/drive unit.

You may also want to look at the Hypertherm Sensor PHC Height control.....if you are looking for highest performance with all the mentioned features....that is designed to work with a high frequency start torch...then this may be a good choice. Here is a link:

http://www.hypertherm.com/en/Product...sensor_phc.jsp

Jim

[sunmix]

Nevermind then! You have helped me ALOT!!! Thanks Jim!

The owner of Campbell THC replied recently, he said that I can add an ohmic detector. What a whiz! =)

[sunmix]

Hey Jim

Just want to tell you that I really appreciate what you have thought me about THC. I know you work for Hypertherm, but there are peoples outside who are trying to flame someone for a certain product. I see you as a very humble person, even you're working for Hypertherm you surely will help someone in other THC products. I really admire you.

Really thanks for helping me out.