KJP Hardwoods

Good morning,

Living in Canada, we recently picked up some of KJP Selct Hardwoods prefinished plywood 1/8" TruFlat Starter Pack but we are struggling to get through the material.

I have seen some posts about people that have used it and I was hoping to get some advice on the settings that people are using to cut through it.

We’ve done a deep clean so I believe we are good in that respect and believe its just settings at this point.

Cheers!

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Your best bet is going to be to do a pretty standard material test that described the number six on this list:

It’s quick and easy, in about five minutes you’ll have the perfect answer for your specific material. Then if you have a minute you can tell us what’s best — since it’s a fairly niche material any research that you do may help everybody else that comes later.

Once you set up the material test, you can use it over and over for any new material that comes your way, making this process even faster. You’ll find that it is almost always quicker and more accurate to test than it is to ask and wait for a response, it’s a great technique to know.

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Thanks for the quick respond and my apologies as I should have mentioned that I have tried my usual material test but the results were less than ideal.

I did take the best of the lot and tried it on just a simple square and it did cut through MOST of the way, however trying the same settings in a more complex design did not come close.

Seemed odd to me so I thought I would try my hand here. :slight_smile:

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It’s hard to know what advice to give you because you don’t say what machine you have.

Also that number six shows you the spreadsheets of suggested settings, you might be able to find some guidance in there

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There aren’t that many variables. Increase the power. If it’s maxed out, decrease the speed.

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Often, plywood can have fillers in voids of the interior ply that will not cut.

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In a complex design, the head has to keep changing vectors while on a straight-away it moves more steadly. The software actually makes adjustments about power depending on the speed but may overshoot a bit as before there would be a hole where it changed direction (which is what it used to do) . It is a very delicate balance and IMHO the better side of it.

I would look and see if your plywood has MDF in the middle as there is much variation in how it is made, but even the best cases is harder (and dirtier) to cut than most other cases.

I just checked and their plywood is MDF centered.

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If memory serves, Houston Acrylics just started carrying TruFlat. You try reaching out to them on FB or Instagram - they have a GF settings for pretty much everything they sell.

Good Luck!

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Hi thank you all for the responses.

Yes, the material does have an MDF core.

I started from scratch, cleaned the machine and did a test cut using the method above. Full power and started at 135 without success.
I was able to get the best cut (dropped right out) with 120 speed and full power on a simple square.

I then pulled a small flower from the gallary and cut that out. Little petals and about 3/4 of an inch high. Perfect cutout on those settings.

I go back to the welcome sign with sunflowers from the design catalog, use the same settings and wasted another 1/2 sheet of material. It didn’t even cut half way through.

I don’t get it. How can the results vary so much from one design to the next on the same settings with the same material (not the first time I have come across this either).

Finding it hard to get reliable results. :frowning:

FYI this is a pro machine.

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Interesting. They propose 200 speed and full power. I was unable to cut it at 135 speed\full.
Does anyone know if the lasers power demishes over time?

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In general, with wood, there is never the same material as even different places on the same piece may vary considerably. However, there can be other causes. I drove myself crazy (short drive) getting a variety of results, some of which were about the material. After about a year I figured out that the magnets I was using to hold the material down would shut down the carriage fan and there would be a slight candle-like flame. I realized sooner that anytime that flame showed up the material would not cut through and often ended up using a jeweler’s saw to finalize that part.

Looking at the unsuccessful cut you often see fine smoke trails that tell a lot about what is happening at that place and time in the cut. If the trails are running straight to the front then the carriage fan is blowing, if not and the trails wander or go off to the left, then the air is not moving fast enough and you will get that little “candle flame” that prevents a full cut.

Even turbulence can cause this. When cutting near the top of the wood (usually more than 3 mm) the fan is blowing from beyond the top and gives a problem that I solved by putting a board of the same thickness above so there is no disruption of the airflow. I have even seen it with something like a bedpin causing that turbulence.

Of course, natural material can be different from sheet to sheet, or even on the same sheet in different places. In that case, I try to set the cut deep enough to cut the worst of it, but even then that is sometimes not enough such as this…

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Certainly. CO2 laser tubes do “age out” over time. One early estimate of the GF’s tube life was ~2000 hours.

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First I would try to find out if there was a larger problem. This might not be about your material, But to be sure about that we have to isolate the material as a variable.

I would try to run a gift of good measure on proof grade material and see if it behaves as expected. There are a lot of possibilities as to why you may experience a change in your power level, a deteriorating tube is thankfully near the bottom of the list. It’s much more likely that there’s some portion of your cleaning procedure that wasn’t done correctly, such as missing a critical step or inserting your mirror and upside down.

You can narrow the possibilities down by running a gift of good measure with known proof grade materials. If that doesn’t work, then there’s something else going on. It might be the tube, but it’s more likely something simpler.

Even if you’ve had your laser for a long time it’s not a bad idea to go through the documentation for cleaning and make sure that you didn’t miss a step. I know there’s been many times where I have been moving quickly and skipped something.

You can find it here if you don’t have the link handy.

https://support.glowforge.com/hc/en-us/sections/11792691970075-Cleaning

If you go through the cleaning procedure and you’re set up correctly, and you’re still having trouble with the gift of good measure, the next step is to take a look at the standard troubleshooting for cut issues which you can find in number five on this list:

Again, apologies if this is all too rudimentary, but like many of us you’ve had your machine for a long time and it’s easy to skip a step when you think that you have seen it all. I still refer to these lists if I have some sort of an issue, it just helps keep me on track to be thorough.

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In general I don’t recommend using that kind of slow speed for anything. There are a few compelling reasons for this, but the biggest one is that you generally have a higher risk of fire the slower you go. I would probably aim toward two passes at a higher speed than trying to go down that low.

Of course as with anything that has to do with custom settings and safety, you should take my advice with a grain of salt but that’s just been my experience.

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Living in Canada, getting PG anything is difficult amd expensive, as we hgave seen from so many of our Canadiam friends. Trotec is in Canada and they should have laser friendly wood in Canada also. I would still avoid any MDF centered plywood for the reasons noted.

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I just cut this material. I used med walnut plywood and changed speed to 116. It cut through, but there was a tiny bit of flame, so I would probably up the speed a bit next time. (full power, 1 pass).

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When you discuss settings involving full power you need to tell us which machine you have because full is different between a pro and a plus and a basic. If you have a plus, it would be handy to know if you have one of the old ones that was a 45 W laser or if you have one of the newer ones that has the 40 W.

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Sorry, it was on a Glowforge pro.

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I hear ya…I did originally try 2 passes at full power and 135 speed without any success as well. My thought was that if it didnt get thru at that speed, it wasn’t going to get thru at faster.
That being said, do you do 2 passes (as in the setting) or do one pass, change settings (ie depth) and run that through?

I do almost everything in one pass, but I stick to 1/8” material generally.

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