Hello, very new here, looking for info/insight on used DHC

[VPT]

First off I am very very new to plasma cutting and CNC stuff. Seems very hard to find any info and help on plasmacam tables. I have a few questions if someone can please help.


Questions regarding the HF start. I bought a esab 1250 plasma cutter earlier and now looking at tables. I read where some say the newer DHC tables are designed to take HF start plasma cutters, is that right? I also read precautions can be made to save the electronics form the HF, any input on those? Is it inevitable death for the electronics mainly the control board using a HF start plasma? Would separating the control box/board from the table and isolating it help protect it from the HF? Can the HF start be disabled in the ESAB?

How bad are the DHC tables compared to the DHC2's? What are the advantages/disadvantages of both? Also the same question for the software of the older tables and newer? Is it very hard to set up the older software to cut quick brackets or exhaust flanges for turbos and heads?

The table I am going to look at this weekend is not hooked up so I won't be able to see it run although the seller swears no problems. How much should I expect to pay for a used 2005 DHC table? The table has been used too, not a hobby garage table.

Just going threw all the possibilities here because after a winter of numerous unexpected bills, buying the plasma cutter, and now the table I am near dead broke for any sort of spending cash and don't have the option of buying yet another plasma cutter for awhile. I would really like to get the table working to pay for itself till I can get a hypertherm or something.

Thank you for any help!

[jimcolt]

I have owned three PlasmaCam tables....I can offer you advice.

-High Frequency start is generally not recommended for use on any plasma cutting machine that uses a standard PC or Laptop as the cnc control. High frequency start plasma cutters generate a 15,000 volt pulse at 2 megahertz.....this is used to ionize the plasma gas which gets the process started. This voltage.....when in close proximity to low coltage computer and drive cables...will drive the computer and drive electronics crazy....and can damage them. Industrial plasma systems all use high frequency start....but they use specially isolated and filtered electronics and cnc controls on these machines. If you disable the high frequency on your Esab....the plasma will not fire. Newer technology air plasma systems use a blowback electrode start that eliminates the high frequency. PlasmaCam genrally does not recommend their systems are used with HF start plasma.

-DHC vs DHC2. From a cut quality, software and motion control point of view...the DHC is very similar to the DHC2. The huge single advantage that the DHC2 has (when used with the Advanced Height Control features) is the ohmic plate surface sensing. Ohmic sensing of the surface recalibrates the height control before each cut cycle...and automatically compensates the height for consumable wear, speed changes, etc. Better cut quality, longer consumable parts life and easier to setup and operate are the advantages. You can buy a new DHC2 today without this function (for less money)....I do not recomend doing so. Unfortunately...the older DHC is not upgradeable to the ohmic sensing technology.

-The value of the DHC machine depends on its condition and what is included with it. Does it have a fume control consisting of an enclosed base and a fan/blower of at least 3200 cfm? Computer? Software included? Art Discs? Anything else? If it is just the bare machine in operating condition with the interconnect cable and PlasmaCam software...it is likely worth about $5k to $7k.

Jim Colt

First off I am very very new to plasma cutting and CNC stuff. Seems very hard to find any info and help on plasmacam tables. I have a few questions if someone can please help.


Questions regarding the HF start. I bought a esab 1250 plasma cutter earlier and now looking at tables. I read where some say the newer DHC tables are designed to take HF start plasma cutters, is that right? I also read precautions can be made to save the electronics form the HF, any input on those? Is it inevitable death for the electronics mainly the control board using a HF start plasma? Would separating the control box/board from the table and isolating it help protect it from the HF? Can the HF start be disabled in the ESAB?

How bad are the DHC tables compared to the DHC2's? What are the advantages/disadvantages of both? Also the same question for the software of the older tables and newer? Is it very hard to set up the older software to cut quick brackets or exhaust flanges for turbos and heads?

The table I am going to look at this weekend is not hooked up so I won't be able to see it run although the seller swears no problems. How much should I expect to pay for a used 2005 DHC table? The table has been used too, not a hobby garage table.

Just going threw all the possibilities here because after a winter of numerous unexpected bills, buying the plasma cutter, and now the table I am near dead broke for any sort of spending cash and don't have the option of buying yet another plasma cutter for awhile. I would really like to get the table working to pay for itself till I can get a hypertherm or something.

Thank you for any help!

[VPT]

Thanks much for the quick reply!

It is just the table with software. Not to worried about the other stuff yet since I have extra computers I can use and being a fabricator it won't take much for me to enclose the bottom and evac it.

So the DHC will sense work height one time and than stay there for all the cuts?

If I really had to use the machine now with the HF cutter is there much I can do for shielding? What part causes the HF effect more, the plasma cutter itself or the torch end? If I wrapped all the table wires in shielding wire and partially build a faraday cage around the computer and CNC control would it help? or am I much better off just learning the table for now without the plasma hooked up and wait till funds are available to get a hypertherm later on? I was really hoping to get this thing up and running to make some money back soon to pay for the table and then worry about a new plasma. But if I run a high risk of ruining the control board costing me as much as a new plasma anyhow I will just wait.

[VPT]

Now that I have the table I understand where the HF makes its path to the control board. Threw the plasma cutter control wires from the control board tot he plasma cutter. Two of the wires are sensing wires that hook into the actual power feeds to the ground clamp and torch lead. BUT watching the instruction video plasmacam gives instruction on how to hook up a ESAB 1500, I will have to do some reading and see if the 1500 uses HF start like the 1250 I have. If it sis and they show how to hook on up and use one I won't feel as scared to use it.

I loaded up the software from plasmacam on my laptop to play with and their program like people mention looks dead simple to use. Even for me that have never ever touched a CNC anything before am able to somewhat understand it and can figure lots of stuff out already on my own.

However the former table owner suggested I download draftsight as a CAD program for designing stuff (what he uses for everything in his shop and quite an impressive shop it was!). Now while I can use the tools to draw simple circles, arches, square, and whatnot I am still at a total loss on the whole deal of how people know what the measurements are of stuff when it is on the screen. Even on the plasmacam software I don't see anything that tells you this circle/hole is this big and this far from this edge and the like. Anyone have some hints for me on this? The best I can figure out right now is a questimate by counting the dots on the plasmacam screen.

I guess I will be spending allot of time on cnc boards and stuff for awhile till I can figure stuff out.

He did have the table hooked up when I got there so I was able to run it threw all its paces. He did take some time and show me a few things on the software as well which helped me.

[VPT]

Built a cabinet to hold the computer today, formatted the hard drive, reloaded windows, plasmacam software, hooked everything up, turned everything on, plasmacam software can't see table...

I had a problem in the past of the printer not working off this computer randomly one day. I just assumed it was the cheap printer gave up the ghost but now I am thinking the printer port may be bad on the puter. I came in for a break and will try another spare computer tomorrow.

I have spent a few hours watching CAD tutorials on youtube last night and this morning. I wish more of these guys making these tutorials spoke better english lol. I figured out how to see measurements but I wish I could see them in real time when making the circles or square or whatnot. I am sure there is probably a way, just have to watch about 12 hours more of lessons. lol

[muzza]

It's quite a while since I used Plasmacam but from memory the f10 key will give you a measurement, if anything is selected before hitting f10 it gives total cut length or you can measure point to point by having nothing selected, press f10 and then select the end points of what you want to measure.
Murray

[planetxfred]

I have a DHC. The height control works fine, just keep an eye on it, and occasionally re zero it to the surface. It tracks well to maintain the cutting height. I am happy with my DHC.
As far as drawing, I have made some fairly complex drawings with the software (3.11), just takes a bit of practice. It draws things at full scale, so if you draw a line 3 inches long, it will cut a line 3 inches long, regardless of the size on the monitor. Draftsight is a good addition.
When something is hilighted or selected (green) and press F10 it will give the path length and number of paths. To measure a circle, draw a line through the center of the circle, trim the ends to the circle, hit F10 and you will see the length of the line (dia).
In my opinion, sell your ESAB and get a Hypertherm. You will be ahead, and less risk of frying a $2k controller.
Fred

[Black Forest]

Is that the only way to get the diameter of a circle in the PlasmaCam software? Is the software parametric?

Meaning when you are designing something using the PlasmaCAm software how do you change the dimensions of a circle once it has been drawing? Can you not just click on the circle and enter the dimension you want?

Surely to re-dimension objects there must be an easier way.

[muzza]

Yes, there is a scale function where you can enter a size or value
Murray

[jimcolt]

You can unhighlight whatever part you want to measure, click on view, then Measure, click on one side of the circle, then again on the other side....you have your measurement. Works just like most CAD programs I have used!


Jim Colt

Is that the only way to get the diameter of a circle in the PlasmaCam software? Is the software parametric?

Meaning when you are designing something using the PlasmaCAm software how do you change the dimensions of a circle once it has been drawing? Can you not just click on the circle and enter the dimension you want?

Surely to re-dimension objects there must be an easier way.

[VPT]

Yes, the circle can be measured in plasmacam and scaled larger or smaller. In fact I have been playing primarily with draftsight and find now most things are easier to do in plasmacam itself. However with practice and time I can see that an actual CAD program like draftsight can be more useful for more precise measurements, drawings, and whatnot. I am a totally new to all this CAD and drafting, and stuff so no matter what I use or do it is all new and hard for me at the moment.

I did figure out much more stuff about draftsight and did finally figure out how to get measurements and some stuff, it is coming to me slowly but surely. So much information in fact that I have had to go back and rewatch a couple tutorials to remember what I just learned the other day.


The biggest thing now is font/text... A guy would think plasmacam would include a font in stencil format for a table that cuts metal. I really wish i could find a dxf file of stencil fonts all ready to go so letter centers don't fall out. I really don't want to go in every time I want to cut letters or numbers and add brackets/bars to the centers.

Another thing too is I have been working on 3.08 (I believe), I need to get the 3.11 update. I just sent in for transfer of ownership today so I hope to update soon.

A final thing. My Z axis sounds like it is dry (chatters) when going up or down. If I put pressure on the motor to the side a bit the sound goes away. I tried adjusting the two screws tighter and looser and it did get a bit better but still there. I also tried lubing the screw and that did nothing. I am thinking something inside of the motor itself is dry and causing the chatter. Anyone ever open up the Z axis motor? Is it ill advised to do? I was thinking of just poping the top cap off to see what I can see. I may not be very computer savvy but when it comes to hand on mechanical and electrical I am the guy. Is the DHC2 update still and option anyone know and how much is it? Just looking at my options.

[muzza]

Stick with it, you'll be saying in no time that it's easy

The X axis is driven by a stepper motor so no don't pull the end cap off unless you want to buy a new one and on Plasmacam it's a proprietry motor not an off the shelf stepper. By all means pull apart and clean and inspect the z axis itself that is more than likely where you problem is.

As for a stencil type font there is a standard windows font called stencil which is upper case only and gets a bit boring but you can find others here http://www.dafont.com/
Murray

[VPT]

So these steppers half way down the page in the link isn't plasmacams rebadged?

http://www.haydonkerk.com/?TabId=66

[jimcolt]

The best way to troubleshoot anything PlasmaCam is to get on their website and join the owners group. There are 7 or 800 users that own PlasmaCams.....ask a question about the z motor on your machine and you will get all kinds of help from others with the same machines.

Jim Colt

So these steppers half way down the page in the link isn't plasmacams rebadged?

http://www.haydonkerk.com/?TabId=66

[SignTorch Vector Art]

I think the plasmacam stepper is a little strange, it only has 3 wires and a case ground connecting in the wire harness, I haven't studied it, but that is perplexing. Not much to see inside.

[VPT]

^ that is the DHC2 right? The DHC is a smaller stepper motor which I read many complain is underpowered and slower than the DHC2. I don't mind slow or under powered so long as it works right. If the smaller DHC stepper looks anything like that one inside I am thinking at least one fo the bearings may have dried out and is on its way out. I am still very tempted to pop just the top cap off and see whats inside. If it is about the same as the DHC2 pictured I would not be scared at all to open it up and replace the bearings.

But then I also wonder if a bigger stepper could be used without much issue. Like if the DHC2 style stepper could be installed without any controller mods and maybe just a software tweak, if even that.?.

[VPT]

The best way to troubleshoot anything PlasmaCam is to get on their website and join the owners group. There are 7 or 800 users that own PlasmaCams.....ask a question about the z motor on your machine and you will get all kinds of help from others with the same machines.

Jim Colt

So these steppers half way down the page in the link isn't plasmacams rebadged?

http://www.haydonkerk.com/?TabId=66

I am working on it, I faxed in the ownership transfer yesterday.

[SignTorch Vector Art]

^ that is the DHC2 right? The DHC is a smaller stepper motor which I read many complain is underpowered and slower than the DHC2. I don't mind slow or under powered so long as it works right. If the smaller DHC stepper looks anything like that one inside I am thinking at least one fo the bearings may have dried out and is on its way out. I am still very tempted to pop just the top cap off and see whats inside. If it is about the same as the DHC2 pictured I would not be scared at all to open it up and replace the bearings.

But then I also wonder if a bigger stepper could be used without much issue. Like if the DHC2 style stepper could be installed without any controller mods and maybe just a software tweak, if even that.?.

That is not DHC2 per se, because DHC2 (or not) is a software issue, I assume it is the current standard Z motor.

I never had any trouble taking motors apart and putting them back together. I imagine most are (made to be) hand assembled anyway. These especially because the bearings are loose slip fits.

I just don't know about swapping motors out though, if there's any difference in the control box or wiring or step logic. It's probably best to just get the right motor and not risk potentially damaging the control box.

[VPT]

From what I understood of the very few people that got the DHC2 upgrade, is that all it was is the Z motor, software, and possibly wiring. But The info is very vague and sparse.

I as well have torn down many of motors in my life and most times don't have problems cleaning them up, fixing them, and getting them back together and working right. However every now and then there is that weird one with odd ball fingers, springs, balls, and whatnot that just falls into a million pieces when you remove the cover and just can't go back together without some elaborate jig. lol When I get some time I will tear into mine and see whats going on. Something for sure is dry in it and I am pretty darn sure it is a bearing. Unless one of the bearing seats loosened up to the point that it doesn't hold the race any more and the bearing is just flopping around causing the chattering.

[geo4932]

^ that is the DHC2 right? The DHC is a smaller stepper motor which I read many complain is underpowered and slower than the DHC2. I don't mind slow or under powered so long as it works right. If the smaller DHC stepper looks anything like that one inside I am thinking at least one fo the bearings may have dried out and is on its way out. I am still very tempted to pop just the top cap off and see whats inside. If it is about the same as the DHC2 pictured I would not be scared at all to open it up and replace the bearings.

But then I also wonder if a bigger stepper could be used without much issue. Like if the DHC2 style stepper could be installed without any controller mods and maybe just a software tweak, if even that.?.

The z-motor will lift over 20 pounds. Check your settings for the Z-axis. The Z-axis speed for a DHC must be under 50ipm.
You can lube the acme screw with white lithium grease.

George

[VPT]

Thanks, I will check the IPM setting next time I have the computer fired up. It may be awhile before I can get back to the table, I am swamped with work and it doesn't look like its going to let up soon. I'm not complaining though.

[VPT]

It has been awhile but I finally sold off the esab and got a PM 65 and made some cuts! Now I have new questions lol. First question, I have been cutting 16G and 1/8" sheet and had problems with the 16G warping and causing torch hang ups. Is there a "sweet spot" minimal material thickness that doesn't warp easy but isn't excessively thick for simple signs and whatnot?

Second, with the DHC I see some voltage shift height control stuff in the software. When I first started cutting some metal this was all set up with default settings and did work a bit but when coming up on a warped section the torch lifted but not fast enough and then it didn't come back down fast enough after going by the warped section causing a very long arc and a bad cut. Since the height problems I have been just cutting with manual height control and cutting one cut at a time. With the thicker material there is no problems of warping.

On a side note I also am waiting for my fine cut consumables to come in. Possibly with the fine cut and less heat input I will get less warp on the thin material?

Some pictures of just a few things I have done in only two days of playing around and cutting.

[planetxfred]

Looks like you are making progress. What are your settings for Z speed?
To minimize warping, work at getting faster cut speeds / lower amps. That should also minimize the dross on the bottom.
Make sure you follow the proper procedure to set the height and arc voltage shift & re initialize. These all affect the height control and how well it follows the surface.
Fred

[VPT]

Thanks! I have the Z speed set at 33ipm right now. When I get close to 50ipm the Z motor starts to act up a bit. I have been experimenting with cut speed and amps more and more and do notice less dross (sometimes even none) and less warp like you mention. I am still waiting on the fine cut parts and am hoping that will also help keep warp down.

Would it be better to cut at a higher amp (65) with a higher cut speed or a less amp (like 45) with a bit slower cut speed? Likewise would it be better to cut as low as 20 amps with as fast of speed as possible?

I also have yet to touch or even look at air pressure controls on the PM65. I didn't notice any problem with the air side at all so I haven't touched it at all yet, just playing with amps and speed. I have been getting great cuts even with the standard drag shield that came with the torch. It has also been saving me trouble I believe when traveling over warped areas and the tip would drag a bit on the material.

I will have to read and play with the voltage shift and height control more when I get time. It would be nice to have that ohmic option for thin stuff.

Not sure if I posted them, these are a couple of the very first cuts I made. The first video the speed is way to slow, cut paths are all broken up (had to adjust my link paths settings), and stuff. The second video is the downloadable car I found somewhere. On the car I had the height control shut off and it worked good. Still to slow of speed and stuff but better.

http://www.youtube.com/watch?v=VrizjO2v ... XyT-AmpRNw

http://www.youtube.com/watch?v=8wQEOdiF ... XyT-AmpRNw

[planetxfred]

I prefer to cut a little slower with lower amps (to reduce the shaking at hi speeds). I just finished cutting a 4X4 sheet of 14 gauge HRS shapes, running at 45 amps and 220 inches per min. I got about 200 parts from the sheet. Even at this relatively mild pace, it takes less than 10 seconds per part to cut and another 10 seconds to run the wire wheel to deburr both sides of each part (nearly no dross top or bottom). Cutting at twice the speed would reduce the total time (for the job) only a little bit.
Fred