[larry lee]

Multiplaz-3500 Evaluation, Part 06: Comparing the Multiplaz Cutting Torch (continued)

DISCLAIMER!
Let me emphasize that I will not be able to tell you whether the Multiplaz-3500, or any other piece of equipment, will be a good investment for you. Only you can decide that. My intent is to provide as much factual information as I can about the Multiplaz-3500 so that others in our company can make an informed decision about that. The company has no objection to my sharing the information with you as long as I leave their name out of it and make it clear that I am not endorsing any particular product.
DISCLAIMER!

In Part 05 of this Evaluation, I took the approach of asking what properties (or combination of properties), from a scientific standpoint, would be expected to affect the performance and then looked at those properties for the Multiplaz cutting torch.

Today I will take another alternative, which is to compare units not on the comparability of design, but on the comparability of performance doing the job for which they are intended. That is, compare units that are intended to perform a certain operation, say cutting 6 mm mild steel sheet. The idea of using performance standards (rather than static standards like output current or rate of flow or type of technology) for comparison is one that has gained popularity in the last few decades, and for good reason. So now lets look at other plasma cutting units that could be considered comparable to the Multiplaz cutting torch.

Before one can do that, one needs to decide what properties are important and what the requirements are. We choose the following, based upon the manufacturer’s specifications for the Multiplaz unit:
1. The unit must be self-contained. Only electricity needs to be provided at the site of operation. The AC voltage input may be 115V/120V or 208V/230V/240V or both. The AC input current must not exceed 20 A while performing the required cuts.
2. The unit must be reasonably portable. The weight must not exceed 50 pounds (preferably not exceed 40 pounds).
3. The unit must be able to sever 1/4” steel at an average speed of at least 3” per minute (total length of cut / total time). Multiple passes are permitted within the total time. The unit must have a duty cycle of at least 35% while doing this cut (i.e., one must be able to sever 10.5” of material in one 3.5 minute time period).
4. The unit must be able to produce a good quality single-pass cut in 1/8” steel at an average speed of at least 10”/min.
5. The unit must be in current production and it must be available for sale from the manufacturer in the USA.
6. Complete specifications for input AC voltage/current, duty cycle, and claimed cutting rates for the conditions specified in 3. and 4. above must be available from the manufacturer.

At one time, most manufacturers of plasma cutters produced a small self-contained plasma cutter that would need to be considered. This included ESAB, Fronius, Hobart, Hypertherm, Lincoln, Miller, and Thermal Dynamics, as well as several smaller manufacturers. Today the comparison is simpler as only Hobart, Lincoln, and Miller still offer a machine that meets all (or almost all) of the requirements listed above. ESAB, Fronius, Hypertherm, and Thermal Dynamics no longer list their small self-contained machines for sale, although some are still available in the marketplace. There are also small self-contained plasma cutters offered by several smaller manufacturers, but I was unable to find adequate manufacturers specifications to compare them.

For this comparison, I will use the Miller Spectrum 125C, the Multiplaz-3500 with cutting torch, and the Lincoln Tomahawk 375 Air. The Hobart AirForce 250ci and the Miller Spectrum 125C are very similar machines, as one might expect from the fact that both Hobart and Miller are Illinois Tool Works companies. The two owner’s manuals have many of the exact same pages and drawings, including the same (erroneous) graph of cutting speed vs. cutting thickness. The two machines do use different torches and have a few different features.

One of the problems in comparing manufacturer’s specifications is that the same words mean different things in the different manufacturer’s brochures. For example, what is called the “rated” or “recommended” or “quality” cut is at 22 inches per minute (IPM) in the literature for the Lincoln and is at 10 IPM for the Miller. Lincoln lists 14 IPM as the “maximum” cut, which for Miller is at about 7 IPM. The Multiplaz manual uses different wording. To try to make the comparison more equal, I will list the cutting rates as well as the thicknesses in the comparison table.


TABLE

Comparison of Some Properties of “Comparable” Self-Contained Plasma Cutters

Company_: Miller____: Multiplaz__: Lincoln
and______: Spectrum: 3500______: Tomahawk
Model____: 125C____: Cutting____: 375 Air

Maximum_: 3.2 mm__: 2.0 mm___: 7.9 mm
Quality Cut: (0.125”)__: (0.079”)__: (0.312”)
@ IPM_____: 10 IPM___: 17 IPM____: 22 IPM

Maximum_: 4.8 mm__: Not_______: 9.5 mm
Good Cut_: (0.188”)__: Given_____: (0.375”)
@ IPM_____: 7 IPM____: ___________: 14 IPM

Severance_: 6.4 mm__: 9.5 mm___: 12.7 mm
Cut_______: (0.250”)_: (0.375”)___: (0.500”)
@ IPM_____: 3 IPM___: 3 IPM______: 5 IPM

Arc Volts__: 110 V___: 265 V_____: 90 V

Arc Amps_: 12 A____: 3-9.5 A____: 10-25 A

Arc W max: 1.3 kW__: 2.5 kW_____: 2.3 kW

Plasma
Gas______: Int. Air___: Int. Water__: Int. Air

Gas Flow_: 41 g/min_: 4 g/min___: 96 g/min
@ PSI_____: 40 psi____: <17 psi___: 70 psi

g/min/kW_: 31______: 1.6________: 43

AC Volts__: 120 V____: 120-240 V: 208-240 V

Duty Cycle:
6 mm Cut_: 35%_____: 100%______: 100%

Weight
w/Torch___: 40#?____: 30#*______: 40#

MSRP_____: $1200___: $1995*____: $1710

US Cost___: <$1000__: $1995*___: <$1400.

= includes welding torch and accessories

Int. = Internal

IPM = Inches Per Minute

MSRP = Manufacturer’s Suggested Resale Price


The Multiplaz unit weighs the least, but one would also want to carry along some distilled water, so that would add a few pounds. For practical purposes, the units weigh about the same. Although not given in the table, the sizes of the units with the torch are also about the same, and certainly small enough to be considered portable. All are inverter-type power supplies. Although the arc power of the Multiplaz unit is comparable to that of the Lincoln unit, the cutting capacity of the Multiplaz unit is more comparable to that of the Miller unit. As discussed in Part 05 of this Evaluation, this is due to the very low gas mass flow rate from the Multiplaz cutting torch. The Miller unit works only on 115 VAC; the Lincoln unit works only on 208-240 VAC; the Multiplaz unit works on either with automatic switching. The arc current and the air flow rate are fixed on the Miller unit; you must adjust your cutting speed to match the thickness of the metal being cut. The Multiplaz unit has adjustable arc current, but the gas mass flow rate is determined by the plasma power and cannot be controlled independently. (Not that you would ever want it lower than it already is.) The Lincoln unit has adjustable arc current (10A to 25A) and hence adjustable power (0.8 kW to 2.3 kW) and also has adjustable air pressure (gas mass flow rate). This gives more control over the speed and quality of the cut with metals of different thicknesses. The unit also has an external gas input. With a higher gas pressure (air or nitrogen) it has an even higher cutting capacity. It obviously costs more to provide these features, although most of the higher cost of the Lincoln unit is associated with its higher cutting capacity. The Multiplaz unit is sold only by the company; there are no discounts from the Manufacturer’s Suggested Resale Price (MSRP). The Lincoln and Miller units are available with about a 20% discount from the MSRP.

If one does not require that the unit be self-contained (i.e., an external gas supply is used), the same (or higher) cutting capacity can be had at a lower price, and with lower size, lower weight, and higher electrical efficiency. But in some situations, external gas supplies are not convenient or even possible. In such situations, these small self-contained units are really useful.

to be continued

larry lee

[larry lee]

The value given in the table for the weight of the Miller Spectrum 125C has a question mark behind it because there were different weights listed in different Miller publications about the unit. I checked with Miller and the weight for the current unit, complete with torch, is 31 pounds.

In 2004 the Spectrum 125C replaced the Spectrum Thunder and both weighed 50# at that time. In 2010 the Spectrum 125C was redesigned and as a result the total weight decreased from 50# to 31#. A new specification sheet was issued at that time (July 2010) that listed the new size and weight. Several recent Miller publications list the weight as 50#, but that is incorrect and is supposed to be corrected.

larry lee

[Otto Nobedder]

So far, these comparisons suggest if I wanted one machine to perform many of the tasks I do now with several dedicated machines, The Multiplaz is worth consideration.

I am not in a position to require such versatility from a single machine, but I'm now curious enough I'd love to get my hands on one and give it a workout.

All the statistics in the world are not as convincing as "hands on" experience.

Steve S

[Billbong]

Hi Otto, It's a powerfull machine no doubt, but if you want to do fine Tig type work, it's a steep learning curve.

I bought mine because it cuts out all the extras you need for conventional welding, like special welding rods with different flux coatings, and Tungsten electrodes and Argon bottle rental for Tig work as well as Argon or CO2 mixes for both Tig and Mig stuff......having bought an auto darkening hood, I now don't need it any more.....no arc flash to darken it.

And the cream on the cake is, you can do heating all day like you would do with an Oxy/Acc outfit and it won't cost you more than a few dollars of electricity at 16 cents pre KW/hr, (my domestic rate in Melbourne, Australia).

I would highly recomend having a hands on unimpeded demo session with various thicknesses of metal to get a feel for the method which is totally different to any conventional welding method.

I've had mine for over a year now and will be selling all my conventional welding stuff.
Ian.