Specific letters come out different to onscreen look

Hi there, I have a Neje 40w (15 output) on a 1x1m Cnc board which was custom made for me.

I am currently cutting and engraving my wifes leather products.

The challenge I am faced with is that specific letters have specific issues on them which do not appear on screen. No matter if I engrave on a different spot on the board. Always specific letter that has an issue. Makes me think its the font or image itself? Or lightburn?

See the images, the l in Dlamini always has a small dent in it close to the top. Also some names it is like it Bolds the last 4 letters. Every time. Doesnt change.

Any advice would be appreciated so much as I am running out of time to engrave an order of 116 wallets, mousepads, deskpads etc.

Thank you in advance


It could look like duplicates.

Do you have ā€˜overscanningā€™ enabled in your fill layer? If not, thatā€™s likely the cause.

image

The ā€˜dentā€™ in the 2nd letter above corresponds precisely to where the gaps in the iā€™s are:
image

If the laser is starting right at the edge there, itā€™s probably not firing hot enough while accelerating. If you add a bit of overscan, it gives the laser time to speed up before firing, and will likely solve the problem (notice the red ā€˜movementā€™ lines shown):
image

The ā€˜boldingā€™ of the letters could be misaligned scans. If you turn off ā€˜Bi-directionalā€™ engraving and the bolding effect is gone, you likely have something a bit loose in the machine.

Good morning,

When using the Fill setting I do not have the option on my Lightburn to enable or disable Bi directional Scanning. However, I have gone over the whole machine, which is a month old by the way, fairly new. nothing is loose.

I have set the overscanning up to 4.5% and it seems to have minimized the effect on the L.

However the bolding of the last letters in the names do not go away. Any other advice ?

By the way, I have tried offset fill, which completely solves both issues, but with offset fill there is a line in the middle of the letters, so thats not a solution sadly.

The machine being brand new is actually a strong argument for there being something off still, since you self assemble it - Itā€™s very common for self assembled machines to have a few issues to work out before theyā€™re solid. ā€œLooseā€ isnā€™t quite the right word, but if the belts arenā€™t correctly tensioned it will cause the effect youā€™re seeing.

If you donā€™t have the option to turn off bi-directional, youā€™re likely in ā€˜Beginner Modeā€™, which you can disable in the main settings.

Hi Oz apologies for the long time to reply. Doing multiple jobs.

I have switched off beginners mode. I have bi directional scanning off but the bolding/doubling effect is still there.

I was wondering if the turnaround speed or something is too fast? to make the machine maybe sometimes lose a step when stopping and reversing its direction very quickly? To me the machine stops quite quickly when reversing its direction.

Any other advice?

Oh Also I did not self assemble. It came as is from a reputable company. Cost me $1100.00

I have asked a friend overseas and he said I should look up reverse interval. Can you advise me on that too? What do you think?

Ok so if I slow down the speed, the smaller text at the bottom of the logos are now perfect, no doubling or ghosting. but the Big Logo part has a piece that is a few lines, being off to the left. I will post a picture

Hi there,

I have done a leather deskpad now, and the left line was in two different places for cutting purposes which it should not have been.

I give up.

Please engrave a simple circle on inexpensive material to confirm that the machine is showing no symptoms of backlash.

Hereā€™s a great thread on the subject:

Hereā€™s a robust explanation of what we are hoping or expecting to see.

This is a reasonable possibility. I advise proving out the simple circle first, then reverse interval.
https://docs.lightburnsoftware.com/ScanningOffsetAdjustment.html

This isnā€™t the most relevant document for your laser but it adds a little bit more to the how-to.
https://www.ctrlasers.co.uk/userfiles/downloads/lightburn_setup___backlash_guide_45916.pdf

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