16 Gauge mild steel Testing day

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Ok a few disclaimers before I start. I know the difference between “real scientific testing and what I am about to say”. This was a test just for my own personal knowledge and I am sharing it in the hopes it helps someone, but take it with a “grain of salt”

I got tired of listening to “the man” spout their BS today at work, so I decided it was a good day to take a "mental health’ day and do some testing.

I made this “test cut” part to see if I could find my machines “sweet spot” for 16 gauge mild steel.

Here is a pic of the Sheetcam and the G-codes. I am pretty sure that the f100 means that I had the setting for this to run at 100 ipm.

Here is the G-code:

(v1.6-sc)
G90 G94
G17
G20 (Units: Inches)
H0
G0 X-0.0376 Y0.1386

G92 Z0.
G38.2 Z-5.0 F100.0
G38.4 Z0.5 F20.0
G92 Z0.0
G0 Z0.02 (IHS Backlash)
G92 Z0.0
G0 Z0.15 (Pierce Height)
M3
G4 P0.8
G1 Z0.06 F50.0 (Cut Height)
H1
G1 X-0.095 Y-0.0 F150.0
G1 Y-1.25
G3 X0.0 Y-1.345 I0.095 J0.0
G3 X0.095 Y-1.25 I-0.0 J0.095
G1 Y1.25
G3 X0.0 Y1.345 I-0.095 J0.0
G3 X-0.095 Y1.25 I-0.0 J-0.095
G1 Y-0.0
G1 Y-0.25
G1 X-0.0376 Y-0.3886
H0
M5
G0 Z1.0
M5 M30
(PS150)

So I adjusted the feed rate using the % up and % down buttons in Fire Control.

Well I still was getting what I thought was too much dross, so I decided to "play around and write down my results.

My “data tables” were labeled IPM (inchs per minute), amps, and results…

Now the “results” section is the “grey area”, 1 is really bad and did not cut at all, 10 is the best with “absolutely no dross at all”

Yes, I know it’s totally subjective, and not very scientific, but I found it to be interesting/helpful

I started off with the following specs.

419 pierces
and 40min 19 secs of run time on machine.

My setup is a Razorweld 45, Quincy 60 gallon compressor with a desiccant style dryer that goes into a Moto guard "toilet paper filter.

I started out at 100 IPM, 32 amps and got just ok results. So I decided to start trying some different settings to see what happens.

I was a little surprised…It turns out that my best cuts seemed to be at about the 50-60 IPM area and at about 30 -32 amps…My fingernail barely caught it.

The 50-60 IPM sounds pretty low to me, but???

Well here is a look at my white board in the shop with my results.

IMG_3260
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IMG_3261
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IMG_3262
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worst.

IMG_3269
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IMG_3270
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Best

IMG_3267
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Overall test sheet. Probably about 40 cuts total

IMG_3263
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That’s actually what you’re supposed to do.

Very common and actually scientific in that you are changing one data point each time and comparing results.

This is assuming all other factors remain the same which…over the course of many pierces, will affect the cut quality given a specific cutting height.

Even Hypertherm’s own manual states one must alter cut height slightly as a consumable gets worn.

But yeah what you posted is very common in creating your own cut chart.

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Can anyone confirm my cut speed from the G-Code was 100 IPM?

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ipm’s were 150. I believe the start of each cut and the last line in the code should match.

i don’t remember what there values are for but it has something to do with the z axis movement. could be raise/lower speeds of the z axis.

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I completely skipped your G code as I was only looking at your written chart.

But that raises another issue now - what is your physical measured cut height?

I know you have lots of threads and generally go against the advice by those experienced, but I can tell you more often than not, your programmed cut height does not always match your physical cut height.

As I mentioned above, to get the most out of your above test cuts, you need to ensure all other parameters are correct and consistent.

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image

Here is what David has taught me…if I paid attention:

Those speeds are the speed of the z-travel.
G38.2 Z-5.0 F100 (IHS is finding the metal: Travel torch down to limit or 5 inches at 100 inches per minute until the IHS contacts separate)
G38.4 Z0.5 F20 (Now it is lifting slowly at 20 IPM up 0.5 inches until IHS switch triggers it to stop; contacts come back together)
The next line of code (G92 Z0.0) after that action tells FireControl/IHS to set z to “0” at that point where it stops.

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I have found many website references for G-Code, but like this one best.

It describes how F code is modal, and is set once, continuing at that feed rate until canceled or changed.

There are many detailed diagrams showy/ explaining the sequence of operations.

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Thank you Bernie,
I am glad to have that link. A year ago, I had saved it as a running pdf (no page delineation) so it was very difficult to read). I have now saved it as a pdf that has page delineations.

Here is the file if anyone is interested for their records.
G-code Explained _ List of Most Important G-code Commands2.pdf (7.2 MB)

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You did not skip my G-code, it was not posted yet. :smile:

Sometimes i have to switch machines to post pictures, so there is a delay.

How does one measure the actual cutting height? I have not done this yet.

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Hmm, that makes sense. I thought I had changed it to 100, but apparently not.

So since my chart was based on percentages I will have to “recalculate” later today.

Thanks. :+1:

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Run this program and measure with a feeler gauge.
cut height test.tap (224 Bytes)

It is programmed at .060

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I believe it states that one must alter voltage to maintain cut height as consumables wear.

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I think you mean feeler gauge

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Auto correct or auto fill! I will fix it.:grin:

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These are part of the IHS cycle. The first line moves the Z down at a modest speed until the tip torch touches the metal and stops when the IHS switch opens. The second line very slowly raises the Z until the IHS switch closes again, taking care of spring back. These are modal, but for Z axis only.

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I need to stop trying to rely on my memory and cite stuff instead :rofl:

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You measure by either pausing mid cut, or running the dry run file that initiates IHS then stops at whatever “cut height” is in the gcode.

I found at a programmed height of .06 my physical cut height was over .085 or whatever it was

So all my processed files are done with a programmed height of .035 to give me the proper physical cut height

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Thanks guys. I am going to make this “torch height adjustment” a priority the next time I get some 'shop time".

I had to order a “faster computer” last night, because these damn CAD programs have been bringing my “El Cheapo” laptop to its proverbial “knees”.

So next week, I should be able to get everything dialed in and tested. :+1:

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It is good time to check the “cut height” AFTER the new computer arrives. Both of my computers that I used with the table have been relatively cheap (<$800). The one required me to set the cut height at 0.022 to get an actual cut height of 0.060 but the new one is spot on with 0.06 giving me 0.06 inches.

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Thanks for the tip Jim.

So here is my plan. See if this makes any sense.

I have never had a problem with using “El Cheapo” to cut out parts/signs. It has been perfectly adequate thus far.

The problem lies with the CAD software.

For example, It takes about 15 seconds for it to respond to me clicking on a line when I am “trimming” lines (I actually counted). So I can click on 10 lines, then come back about 2 minutes later and it is still not done “trimming”. Very frustrating to say the least.

But I have never had a problem when I connect it to the table and actually do the cutting.

Anywho, My plan is to use “El Cheapo” as the machine that I will be using to connect to the table, since it is basically “expendable” and I would rather have it get damaged/dirty at this point.

So I am presuming that this is the machine I need to calibrate… yes?

The new machine is going to be for the actual CAD stuff only, since this one “should” have the balls to run just about any CAD program that I will ever run into.

This one should not need calibrating correct?

Just for reference the new machine is a low end gaming machine with the following specs.

Processor Intel Core i7-11375H, 4 cores 8 threads, 3.3 GHz base clock speed and 5.0 GHz max
Memory 16GB DDR4-3200MHz, Maximum 64GB supported
Storage 512GB M.2 NVMe PCIe SSD
Graphics NVIDIA® GeForce RTX 3060 with 6 GB GDDR6 VRAM
Screen 15.6 inch
Operating system Windows 10 Home
Recommended for Intermediate to advanced user and larger data sets