[InspirationTool]

I've started a 2D CNC guide... I've filled out the general considerations, but I need major help with the numbers for each type of machine in different thicknesses of steel.

Check out:

http://www.jeffalbro.net/cnc/2d-comparison/

Please post numbers and comments and I will fill in and update.

-Jeff

[Apples]

under plasma consunmables.

Put in TIPS and NOZZELS, you could also put in OXYGEN, NITROGEN, COMPRESSED AIR.




PEter]
Australia

[DanOSB]

good job for takin time to do this.. im sorry i dont have any specs right now im still learning.. but im sure someone will chime in..

and little suggestion.. maybe add picture of each item after cut to show the quality in that chart.

and plasma can be purchased for 2000 depending on which model you want..

unless u were talkin about high defition plasma

[InspirationTool]

Thaks for the tips!

I added the consumeables for the plasma. I LOVE the idea of adding pictures of the edges and will do so if I get some.

As for price for the plasma, does that include the CNC table?

And how much better is high definition plasma? Is it better on edge taper?

-Jeff

[DanOSB]

well i got some sample metal from hypertherm.. to be honest.. i couldnt see that much difference comparing about 5 grand machine to 36 grand machine..


i will try take a pictures and send it to ya later on..

hy peformance or something and the 5000 model

[InspirationTool]

I haven't gotten enough information to do a detailed cost/thickness analysis on steel, so I'm just going with the general comparisons.

I've put up the table I'm pretty happy with here:

http://www.jeffalbro.net/cnc/2d-comparison/

I'm still open to suggestions.

Thanks!

-Jeff

[mxtras]

Nice work, Jeff.

Thanks for taking the time! Good information to have all in one spot.

Scott

[bennett71]

Jeff, you should add optics to the consumable section for lasers. Focusing lenses are replaced the most, & internal optics degrade over time. Tom

[Klox]

Jeff,
You can add consumables at wire edm table: Filters & jigs (sometimes the component needs to be jigged eg. very small parts). Also (wire) guides from time to time....

The prices on the machines vary. From about $80 000 (Chinese/Taiwanese machines) to about $1mil for the (Japanese and Swiss machines). Please note that this figures is not 100% correct as prices might vary from country to country.

[InspirationTool]

Thanks everyone! I've updated the page.

I'm still looking for:

# The performance difference between standard and hi-def plasma

# More information on CNC Punch machines. It seems that these machines are no longer very popular.

# Specific cut cost and taper performance on various thickness steels.

-Jeff

[dday92296]

I found your website on comparisons and really appreciate your efforts. I am considering buying a water jet for my steel shop instead of plasma. I don t know which way to go or if water jet is my choice, what machines are NG it is a big investment an it would sure be easier to eliminate some machines. Do you know any sites that have opinions on machines? And what do you think about plasma compaired to water jet for steel plate material up to 2 inches?

Thanks
Jim Sven

[jimcolt]

I have tons of data that will help with comparing the 3 major types of mechanized plasma systems to each other, and to the other processes such as abrasive water jet, laser and oxy-fuel.

3 types of Plasma:

Low cost, gas cooled air plasma, under 120 Amp
-.030" tolerances
-relatively high consumable consumption
-uses only air or nitrogen.....can cause metalurgical issues on edge
-relatively high chance of dross



Conventional industrial oxygen based plasma, liquid cooled, 100% duty cycle to 1000 Amps

-plus or minus .020" accuracy
-excellent edge metalurgy
-relatively high edge angularityelong consumable life, high cut speeds means lower operating cost
-

High Definition industrial multi gas plasma, liquid cooled, 100% duty, to 400 Amps.

-excellent edge angularity traceable to ISO9013 cut quality standards
-excellent hole quality when coupled to a good motion control system
-minimal heat affected zone
-.010" tolerances possible
-cost per foot of cut is less expensive than air plasma due to high speeds and extremely long consumable life

I will look at the site later today and offer my suggestions.

Jim Colt
-

[dday92296]

jim,

what do you think is the better plasma or water?

how do you know so much?

Thanks for input

jim sven

[jimcolt]

Jim

You ask...which is better, plasma or water jet (abrasive water jet)......and there is no one that can answer that for you without first asking some questions!

1. What would you like to cut (material and thickness)
2. What are your acceptable tolerances?
3. Will a thermally affected edge cause any issues on your material?
4. How fast would you like to cut?
5. Is there a cost limit on the cutting process?

A simple comparison.....assume you are cutting 1/2" mild steel plate.....a rectangle 12" x 12" with four 1/2" diameter holes. You have a Hypertherm HPR130 plasma mounted on a precision cutting machine.....and you have an abrasive water jet.

Plasma: The plasma will cut this material at 130 Amps, using oxygen as the plasma gas...the cut speed will be 80 inches per minute. The whole part will be cut in less than 40 seconds. The cost for cutting this part...not counting capital equipment cost...but all other costs such as consumable, electrical, gas and material handling will be about $11 per arc hour. It will cost about 12 cents to cut this part. The edge angularity will be within about 2 degrees, with taper in the holes of about .050" (bottom smaller than the top). There will be a very slight edge (heat) hardening on most materials. Cut part accuracy should be well within .015"

Abrasive water jet: The cut speed will be about 6 inches per minute....meaning the part will be cut in about 9 minutes. The edge will have less than 1 degree of angularty, with less than .025" taper in the holes....the edge will be of very high quality with no hardening...and the cut part accuracy will be in the .005" to .010" range. The cutting cost....including nozzle, abrasive (garnet), electricity will be in the $70 per hour range...so it will cost about $10.50 to cut this part with an abrasive water jet.

These are all relative figures....but are a fair comparison between the two processes. The water jet has advantages in accuracy and in edge metalurgy, while the plasma has a speed advantage......which results in a lower production cutting cost.

Of course the water jet can cut non conductive materials...the plasma cannot.

Capital equipment costs for a precision water jet machine with a 5' x 10' cutting table will be in the $350,000 range, a similar sized High Definition plasma table with a 130 Amp industrial HD plasma will be in the $100,000 range.

I have been with Hypertherm for over 30 years.....and have worked with end users around the world in specifying the correct cutting processes for their applications, I have written many articles about plasma cutting technology for publication in trade journals and have presented technical forums at many SME, FMA and AWS events around the world. I will have an article about optimizing plasma consumable life in the next Fabricator magazine.

Hope that helps!

Jim Colt

[dday92296]

Jimcolt

I replyed hours ago, it must have got lost in cyperspace. That was a very convicing post for plasma. I have three plasma machines in my shop now two of them are 1650's with one more on the way. I wanted to do my research plasma vs water just to make sure I stayed with the times for my new purchase (cnc table). The thing that scares me about plasma is the parts I seen on different web sites for different machines always seem to be crude at it's best but I never seen any in person.

Thanks jim sven

[jimcolt]

In my travels I have found that the vast majority of people that have plasma cutting operations....are not using the plasma even close to its potential. There are so many people that also compare a hobby class cnc x-y cutting machine (I won't name any manufacturers names) that is equipped with an air plasma system ......against the performance of high end industrial lasers and water jets.

A hobby class (my name for it) cnc plasma machine is available for less than $20,000 complete...with a 5 x 10 cutting area. These are great machines for hobbyists or even for a small fab shop that needs to cut relatively low tolerance parts out of metal. The lowest cost water jet system with a 5 x 10 cutting table will be over $200,000, and the lowest cost laser (with 1/2" steel cutting capability) might be over $300,000...comparing machines in this price range against a $20,000 plasma system just is not right!

So, if you need a good low cost, very versatile cnc metal cutting solution....an air plasma with a low cost cnc may be a good choice...

There are also many mid level plasma systems that will use a plasma that is a step above air plasma cutting systems....Hypertherm has a system called the HSD130 that can cut steel with oxygen plasma with an air shield, has a liquid cooled torch...and will provide very high production rates with very low operating cost (high cut speeds, long consumable parts life) as compared to an air plasma. These systems are normally mounted on an industrial quality cnc cutting machine that is designed to operate 3 shifts a day. One of these machines can be purchased new with a 5 x 10 cutting area for somewhere in the $50,000 price range....it is faster and far less expensive to operate (much lower cost per part cut) as compared to laser and abrasive water jet....yet cannot match tolerances from those systems in most applications.

The highest step with cnc plasma would be a high definition class plasma such as Hypertherm's HPR130 or HPR260....these produce better tolerances, narower kerf width, less taper, less dross....along with very high cutting speeds and low operating cost. These plasma systems should be mounted on a cutting machine that is designed for high tolerance production use.....a 5 x 10 version of this type of machine will be priced in the $80,000 to $100,000 range....and will produce parts at very high production rates with extremely tight tolerances that can rival laser and water jet machines in many applications. This is the type of plasma system that should be compared with laser and water jet processes..in all fairness!

Best regards, Jim

[dday92296]

Jimcolt,

can I contact you by phone

Jim Sven

[jimcolt]

Jim, My work cell phone is 603 252 4603

Jim Colt

[Matt Claborn]

Jim,

Do you have any more information on the edge hardening of plasma cut material?

We cut some 2" thick 316L stainless steel on our ESAB Grizzly 1600 GXL w/ Hypertherm plasma unit (don't have model# in front of me), and then went to bevel the edges in our beveling machine. When beveling the edges the teeth were rapidly worn down even though the cutting wheel is rated for 80,000 to 100,000 psi. We were beveling less than the maximum width on the machine, so I don't believe that was the issue (i.e. using a more coarse serration). 316L tensile is about 80,000 to 90,000 psi, so if the material is unhardened the beveler should be able to handle it. But, do you have information on how much hardening is typically experienced when plasma cutting? If it is substantial, we will not try to bevel the material again with a new cutting wheel, as it will probably be eaten up as well (at $1250 a pop!).

Thanks for your help,
Matt Claborn

[jimcolt]

Hardening of the material when plasma cutting is a two part function.....partly related to the temperature that transfers to the base metal and how that particular base metal is affected by heatiing and the subsequent cooling. The second part is more of a chemical metalurgical reaction.
On 2" SS you probably don't have much for process choice ( I don't know what plasma system you are using!) ...but on thinner materials I would suggest using argon/Hydrogen or F5 (5% Hydrogen , 95% nitrogen) to produce the softest edge. Don't attempt to use these gases unless your plasma system is designed for it.

If you are using an older Hypertherm Pac500 system or and HT4000 or 4001 system...then you are using a Nitrogen / water injection process. You can probably improve the edge hardness by submerging the part underwater while cutting...as this will keep atmospheric oxygen from afecting the edge.

Jim