Anybody using the Dynatorch DASH System?

[LeonD]

Just cruising the "zone" this morning and came across your question re; table cutting size. As a rule, we add a minimum of 5" longer than the material and 2" wider. So a 4x8 table's cutting limits would be 101x40. This enables you to have some extra room placing the material and as we all know, sheets are generally oversize anyway.

[CoolHand]

Because the DASH sensor is optical-based it works great on very clean thin-gauge materials, particularly stainless steel and aluminum. However on heavier gauge hot-rolled steel, which usually comes with quite a few stains and blemishes you may encounter some problems. Cutting 1/4" at 100A my DASH sensor would frequently fail to trigger at the set height, causing the torch to pierce extremely close to the plate. This would cause severe blow-back into the shield cap which could then cause both the nozzle and electrode to blow if the system wasn't stopped immediately and the buildup on the shield cap picked off with a knife. Even then the orifice on the shield cap would be blown out. I assume this wouldn't be as much of a problem with a more rugged torch head as on a HyperTherm unit, but our Kaliburn high definition system is very sensitive to pierce height.

This has been a problem on my machine as well.

The DASH seems to work about 90% of the time on clean and thin sheet that has a uniform color and finish roughness.

However, if the plate is rusty at all, or has dark and light spots, or rough spots, or pretty much anything other than pristine metal, the DASH doesn't function at all. Expect a crash ~99% of the time.

Basically, I've only had mine for a few months, and I've come to the conclusion that it's not worth the trouble on anything heavy enough or flat enough to touch off like normal.

When it works, it's cool, but it causes a LOT of crashes, and it has to be calibrated literally for every single sheet you use it on.

I dunno, seems like an ohmic sensor would have been a hell of a lot cheaper to implement, but I had no idea what that even was when I ordered this thing.

Bottom line, it costs a lot of money, and I curse at it a lot more than I praise it. Maybe with time I will find it pays for itself, but the only way that is going to happen is if it stops crashing so damned much. Bad enough that it costs an arm and a leg, but on top of that, it's smoked at least four nozzles all by itself, and for inexplicable reasons.

If I could sort out the problem, I would fix it, but the issues are so transient, I can't replicate them well enough to figure out how to tune them out.

Also, the self calibration thing is not real accurate. What it does, is it uses the laser to look at the plate while it lowers the torch. When the torch touches down, the laser records the reading and stores it as the offset height. I have calibrated it a half dozen times in a row in the exact same spot on a piece of 1/4" plate, and every single time it came back with a different offset. The variance was as much as 1/4", which is why the damned thing crashes into the sheet so much. One calibration it will be fine, the next it's a 1/4" lower, and hits the plate when it goes to pierce.

It's enough to make a man scream and throw ****, believe me.

I was doing test cuts today, and I had to turn the DASH totally off to get the thing to make a cut at all on a piece of 1/4" HR that had been outside (IE covered in rust).

It would calibrate, check the height, then mash the nozzle into the plate, fire the plasma, smoke the tip, and then drag the torch along the surface until the collision detector tripped the e-stop.

If you always work in new thin material that is stored inside and not covered in crud, you'll probably get a lot of use out of one.

If you always work in 11ga and thicker stuff, I wouldn't spend the money.

[magma-joe]

Coolhand,

For me the whole purpose for the DASH is to address the spring back problem with thin materials. It also could allow you to cut .005 thick material as long as it did'nt blow away. This is where it really shines. As you mentioned, when cutting anything other than thin materials I see no benefit to using it over the conventional touch off the material method for initial height sensing as that works very well on the vast majority of material thicknesses. It only takes a few seconds to switch the DASH on and off.


Depending on the thickness, cutting thin sheet is either impossible or it requires constant operator intervention to keep the material from springing back up and causing the torch to pierce while in direct contact with the material. Look at the video of Edwardo I posted in this thread and you will see what I am talking about.

When this occurs it ruins the nozzel and the material is dragged when the torch moves to start the cut. Prior to getting the DASH another thing I had to consider when cutting thin materials was the overall size of the material I was cutting.

If I wanted to cut one 3" x 3" part I needed about a 12" x 12" piece of material for it to have a reasonable chance of being stable enough while sitting on the table slats for the torch to touch off and not move the material and also enough surface area for me to hold down the material with my screw driver to prevent spring back.

With the DASH I can cut a 3" x 3" out of a 4" x 4" piece of material as long as the air does'nt blow it away, LOL. You mentioned in your post, why not use Ohmic contact method? The reason is that normally, thin materials are cut with fine cut nozzels which are unshielded. Ohmic contact only works with shielded nozzels.

I purchased the DASH for a specific thin aluminum job that I do. At the point in time I switch on the DASH to make my cuts I have about $300.00 in time and materials in the part. Any movement of the part or torch misfire turns the part into scrap. It sits up off the table surface from 1 to 2 1/2" when it is being cut. I learned early on that using the touch off method on this part was ocasionally a costly mistake but at the time it was the only option available. So once Dynatorch started offering the DASH it was a no brainer.

Try this test, lay some pieces of .040 or .060 4" x 4" aluminum on your table and attempt 10 cuts with the touch off method and no operator intervention and 10 cuts with the DASH. The value of the DASH will become quite clear to you. I am sure you are also correct about the laser eye difficulty to "see" rusty materials however when the DASH is used with good clean material it allows you to make cuts you would'nt even attempt with the touch off method.

The DASH can be another tool to further extend your air plasmas capabilities. I contacted Leon at Dynatorch support before I purchased mine and he requested I send him a sample of the polished aluminum I was cutting. He tested it and offered some settings and recomended procedures.





Magma-joe

[CoolHand]

Coolhand,

For me the whole purpose for the DASH is to address the spring back problem with thin materials. It is a special tool for this purpose. When cutting anything other than thin materials I see no benefit to using it over the conventional touch off the material method for initial height sensing as that works very well on the vast majority of material thicknesses. It only takes a few seconds to switch the DASH on and off.


Depending on the thickness, cutting thin sheet is either impossible or it requires constant operator intervention to keep the material from springing back up and causing the torch to pierce while in direct contact with the material. Look at the video of Edwardo I posted in this thread and you will see what I am talking about.

When this occurs it ruins the nozzel and the material is dragged when the torch moves to start the cut. Prior to getting the DASH another thing I had to consider when cutting thin materials was the overall size of the material I was cutting.

If if I wanted to cut one 3" x 3" part I needed at least a 12" x 12" piece of material for it to have a reasonable chance of being stable enough while sitting on the table slats for the torch to touch off and not move the material and also enough surface area for me to hold down the material with my screw driver to prevent spring back.

With the DASH I can cut a 3 x 3 out of a 4 x 4 piece of material as long as the air does'nt blow it away, LOL. You mentioned in your post, why not use Ohmic contact method? The reason is that normally, thin materials are cut with fine cut nozzels which are unshielded. Ohmic contact only works with shielded nozzels.

I purchased the DASH for a specific thin aluminum job that I do. At the point in time I switch on the DASH to make my cuts I have about $300.00 in time and materials in the part. Any movement of the part or torch misfire turns the part into scrap. It sits up off the table from 1 to 2 1/2" when it is being cut. I learned early on that using the touch off method on this part was a costly mistake. So once Dynatorch started offering the DASH it was a no brainer.

You say it works for you 90% of the time on the thin clean material you have cut? Do a test with say a .060 4" x 4" piece of aluminum. Do 10 cuts with the touch off method and no operator intervention and 10 cuts with the DASH. The value of the DASH will become quite clear to you. I am sure you are correct about the laser eye difficulty to "see" rusty materials however when the DASH is used with good clean material it allows you to make cuts you would'nt even attempt with the touch off method.

The DASH gives me another tool to further extend my air plasmas capabilities.
Magma-joe

Oh, I entirely understand the advantages of it, what I'm *****ing about is that the thing doesn't often work like it is supposed to.

Yesterday, the DASH crashed four times on a brand new, flat, and clean piece of 16 ga, ruining several parts by dragging the sheet around and spoiling my alignment.

I would love for the DASH to work like it is supposed to, 'cause I gave damned near a grand for it, but it just won't.

I've tuned it, calibrated it, cleaned it, and it still won't work right.

Monday I'm going to clean it again, realign it, re-do the rough calibration, and then re-do the fine calibration on that same piece of 16 ga and see how it feels about working then.

I will say that I'm getting rather grumpy about dealing with it though.

The thing seems to defy all attempts at troubleshooting, and simply re-doing all the same failed steps over an over again seems a touch insane (rather like the definition of insane actually ).

Anyway, if yours always works like it's supposed to, I can understand why you'd be very happy with it.

It's a wonderful idea, if only mine would function properly when I ask it to, things would be all hugs and puppies.

[jimcolt]

Ohmic contact height initial height sensing is designed for thin, springy sheet. This method of finding the surface has been used on industrial plasma machines for years. Ohmic contact (on Hypertherm torch height controls) is backed up by "stall force sensing"......so if the ohmic fails to work due to a non conductive surface, the z axis senses a current increase on contact with the plate.....the amount of force is adjustable by the operator.

The ohmic is a nice method...here's why:

1. Ohmic sensing is done by sensing contact between the shield on the plasma torch and the workpiece. As soon as the work piece is sensed, the z axis reverses, and starts measuring distance after losing electrical contact with the plate.....and rises until the preset pierce height is achieved. This virtually guarantees that the torch will be at the correct pierce height regardless of the "springiness" of the material.

2. If underwater cutting is being done.....ohmic does not work (I suspect DASH does not work either)......so the ohmic is over ridden by the back up stall force sensing.

3. If painted, primed or masked plate...or extremely corroded plate is being cut....ohmic does not work. Stall force covers for these applications.

4. Another benefit of the ohmic force is during steady state cutting.....if the plate buckles or rises (internal stresses or thermal stresses) quickly and contacts the torch shield....the z axis senses contact and rises the torch rapidly until it loses contact with the material, then continues to rise until proper cut height is achieved, a few moments later arc voltage control of the height resumes. This feature....on Hypertherm height controls for the last 15 or so years, minimizes the chance of a part being ruined by plate cotact mid cut.

The DASH system is nice, Ohmic contact is nice.....but they all have their limitations...it is best if the initial height sensing has a backup that helps to cover its limitations! The keu to plasma system long consumable life is with accurate, repeatable initial height sensing, which results in accurate pierce height. One pierce too close to the plate ruins the plasma nozzle....

Jim Colt