Darkly Labs Community

So many cuts needed

On the spec for EM2 it states that you should be able to cut 3mm ply in 2 passes at a speed of 300.

 

But I am finding that I need about 7 cuts at a speed of 130.

 

What I am I doing wrong.

 

Alan

Hi Alan,

There are many variables which can affect the quality of cut.

  • Type of plywood (type of timber, type of glue)

  • Laser calibration

  • Cleanliness of lens/es

  • Flatness of material

  • Air flow above and below timber

  • What you are cutting the material on

  • Humidity of the room

  • Type of air assist used

  • Angle (precision) of air assist

For reference I usually cut 2.5mm plywood (designed for laser cutting with a balsa wood core) at 260mm/min and it takes 2 passes. I clean the lens before every job. I have calibrated my laser to the timber I am using. I hold the plywood completely flat on a metal sheet using stacks of magnets to allow good airflow below the plywood. The original air assist is used as I believe it gives a better finish and it is positioned precisely on the cutting point.

After all this there are often some parts of the job which are not cut through completely and I have to go over those parts with a blade. Using a 5W laser diode you have to come to expect this. I wouldn’t try and cut anything thicker than 3mm.

 

Hope this helps,

Jeremy

 

I was wondering if my offset is wrong  (9mm)after calibration.

 

I followed the instructions and found line 9 to be the thinnest and entered 9 giving me a offset of 9mm.

Is this correct or I am inputting the wrong valve.

 

Another question should airflow be on when carrying out a calibration.

 

Alan

Hi Alan,

9mm is quite a large offset. I would recommend trying another calibration.
The air-assist does not need to be on when performing the darkly labs calibration on paper.

To calibrate my laser to the material I use my own calibration file similar to darkly labs. Because I don’t use the silicon mats I have just set my offset to 0 and just include the offset in the material height. 

For my setup I cut my plywood at a height of 25.5mm which includes an offset of about 4mm.

I think you have seen the images of my setup:

https://darklylabs.zendesk.com/hc/en-us/community/posts/115003000711-Best-way-to-prevent-heat-spots-under-work

I have found this setup to be much more reliable than using the silicon mats.

 

What type of plywood are using though?

 

Jeremy

 

Using normal laser ply but have some laser lite ply on order to try

It seems from other comments is the calibration is not the best. To me it looks like I could play around with just my offset to get better results

Alan

Alan,

My callibration normally comes out with a value of 4-5 using the cutting mats.

Have you got your lens correctly located in the tube holder? The grub screw should just drop into the recess.

For 3mm ply I use 100%, 5 passes, start height 11.5mm and a speed of 200mm/min, this normally cuts right through with the occassional bit that may need a knife to releive it.

Martin

Hi Martin

I wonder if I am reading the calibration sheet wrong as you seem to have a offset of more than 4mm lower than me and

this my explain why I am having to do a lot more cuts than most people…

 

Can some please explain how to do a the calibration correctly

 

This is the only issue I have at the moment compare to what other people are stating with some excellent results including some lovely

English bond brick work in )) gauge.

 

Alan