New PG Cherry Scoring too strong

dr.krawetz · August 16, 2018, 2:21pm

I’ve seen a few comments about other people experiencing problems with the new power settings.

Last month I made a bunch of double-sided keychains using PG Medium Cherry. They looked wonderful. It includes engraved text on the front, and the back has an engraved pattern and some scoring.

Yesterday, I tried the same pattern. The engraving is much deeper (not good; engraving on both sides makes it brittle in the middle). And scoring is way too strong. I can hold it up to the light and see holes where the scoring went all the way through at every corner and where circles start/stop. Even scoring that doesn’t go over the front-side engraving (engraving on the opposite side) makes tiny holes.

I have tested with a simple scored circle on PG Cherry. High quality and draft quality scoring both create these tiny holes that go all the way through.

Is there a long-term solution for this?
Does anyone know the previous PG Medium Cherry settings? Those settings didn’t cause these problems.

rpegg · August 16, 2018, 2:51pm

In 18 months of operating a Glowforge laser, the scoring settings have always created the over power points at the start/stop point of a line. Some times it goes through the material, some times not. Just might not have noticed them. Haven’t seen any changes to settings in about a year.

pubultrastar · August 16, 2018, 3:05pm

I’m getting the same results, and have manually altered my scoring on Cherry and Walnut ply. Doesn’t seem to be a problem with draftboard. I had done a very complex design in some walnut, and the proofgrade settings for scoring charred my piece, with some of the lines actually going through the entire piece of 1/8" ply. I’m on my 4th , and the power in each of them has been quite different. I’m really not interested in sending another one back, so I’ve just manually made adjustments. Nice to know that I’m not the only one.

dr.krawetz · August 16, 2018, 3:36pm

Hi @pubultrastar: Mind if I ask what settings you’re using?

rpegg · August 16, 2018, 3:38pm

Have had three units over that time with the same results. (Was involved with the Pre-release test efforts.)

pubultrastar · August 16, 2018, 3:42pm

I’ll have to look when I get back home, but I know for the pieces I printed yesterday on Cherry, I increased the speed from 128 to 150, decreased the power by a few numbers. I don’t recall what I did for the walnut, but I can search my notes.

Jules · August 16, 2018, 5:41pm

Hah! Wasn’t sure, but I did actually record those numbers…spreadsheets are wonderful things.

Light or dark score?

dr.krawetz · August 16, 2018, 6:38pm

Hi @Jules, Oh! Both please!

Jules · August 16, 2018, 6:42pm

Okay, let’s see…Medium Cherry Ply:
(And I only kept it for the Plywood…hope that’s what you need)

Light Score: 194/15
Dark Score: 168/30

dr.krawetz · August 16, 2018, 9:06pm

Thanks @Jules!

That gave me a good place to start. It took a little testing (glad I keep all of the tiny scraps around).

What works for me: PG Medium Cherry Hardwood, Engrave=450/28/450 (power/speed/LPI), Score=195/12, Cut=PG (that’s 189/Full).

I’ve added it to my own spreadsheet. (Didn’t expect to need to track PG settings.)

For some reason, the current default PG settings for Med Cherry Hardwood are Engrave=1000/Full/450 (that’s way too deep), Score=125/11 (that’s also way too deep).

Jules · August 16, 2018, 9:13pm

Well not really…it might be a little too dark for your current liking, but keep in mind that the faster the speed, the less burning there is. So speeds of 1000 can get by with more power. (You can also just reduce the power and leave the speed the way it is - but the dots where the machine pauses to turn corners are because of the pause, not really the settings. It only takes a fraction of a milli-second to burn it a little deeper.)

jbmanning5 · August 16, 2018, 9:26pm

If you slow it way, way down, you can minimize those. I mean in the neighborhood of 125-135. Just have to adjust power accordingly.

Edit : Lol teach me to read everything in a thread. The reason they are that slow in PG settings is to help get rid of the overburn in corners. If that’s too deep, and you don’t want burns in the corners, lower the power even more.

Jules · August 16, 2018, 9:25pm

I haven’t been seeing it very often these days…might be the designs, but I did notice it on one the other day that had a lot of corners. It wasn’t particularly critical, but I might slow down the next one to see how it does.

vee · August 18, 2018, 6:44pm

Thanks for letting us know about this. I’m so sorry for the trouble. We’re looking into it now, and we’ll update this thread once we have more details.

BSheremeto · August 21, 2018, 5:37am

Yep, I never run a score or cut with lots of sharp corners above 200, and on some thin materials I simply can’t use score

jaz · August 20, 2018, 11:22pm

Can you let me know which of the Medium Cherry Hardwood engrave settings you are using?

dr.krawetz · August 21, 2018, 2:56am

Hi jaz, I’m using PG Medium Cherry Hardwood, Engrave=450/28/450 (power/speed/LPI), Score=195/12, Cut=PG (that’s 189/Full).

The score still makes a few holes (very few). @BSheremeto said to use a slower speed, so next time I test, I’ll try around 150/10.

jaz · August 24, 2018, 10:55pm

I’m so sorry that wasn’t clear! Could you please let me know the Proofgrade engrave setting you were using that caused the original issue? For example, SD Graphic, HD Photo, etc.?

dr.krawetz · August 29, 2018, 4:18am

I was using PG Medium Cherry Hardwood.

If I switch from PG Medium Cherry Hardwood (engrave SD) to manual, it says 1000/full/270. That’s way too strong – engrave goes more than half-way through the wood.

PG Medium Cherry Hardwood (engrave Draft) is 1000/full/195. Again, way too strong.

PG Medium Cherry Hardwood (engrave HD) is 350/21/450. Still too strong, but not as bad as the others.

jaz · August 29, 2018, 11:41pm

Thank you for your reply! I’m looking into it now, and I’ll post as soon as I have more info.