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Member postings for Martyn K

Here is a list of all the postings Martyn K has made in our forums. Click on a thread name to jump to the thread.

Thread: Cheap Chinese Laser Cutter
09/04/2020 10:39:45

I appear to have a fix after posting my problem on the Lightburn forum

I got a very good suggestion which didn’t work unfortunately, however an explanation of laser mode gave me the clue I needed. I simply dropped the cut speed down from 600mm/min to 300mm/min and it worked perfectly, with nice clean corners.
I also tried with an ai file type and join selected shapes (suggestions from the Lightburn forum) . In fact, the fix may be a combination of all 3 but there was no obvious improvement until I reduced the speed. I need to experiment a little more but the quality of cut now is very much better.

The problem was that the head could not accelerate or decelerate fast enough to keep the laser going at the desired power.

Simple really.

Martyn

08/04/2020 22:31:11

Hi Barrie

Good question. I am absolutely sure, but I will double check in the morning. The wheel outer stutters and that is definitely a circle.

Martyn

08/04/2020 20:51:17

I have tried setting $32=0 - that gave me back my power but the cut path still stuttered in the same places. So now its back to $32=1 and reduced power again. The main wheel circle - which is definitely one object also stutters.

I still think this is a controller issue struggling to process commands in a timely manner.

So, starting from scratch, using the little drawing package in Lightburn, I drew a random shape of a square overlapped by a circle with a few random lines (scribble) intersecting the square and circle.

It worked perfectly, I had full power back (or it appears to be), no stuttering and nice clean cuts. The only gaps were at the corners where the power reduced as it slowed down.

So, is the problem the way that the program is interpreting the DXF file and generating GCODE?

I will get to the bottom of this...

Martyn

08/04/2020 19:53:57

Thanks for the advice.

The settings on the controller are:

$30=1000

$31=0

$32=1

which I think is correct.

I also fail to understand why the laser only appears to be running at about half power

I have also grouped the object so all the arcs should now be contiguous.

Any thoughts?

Martyn

06/04/2020 23:21:24

Thanks both

I think the psu is OK. If I run the gcode using an early version of grbl1.1 which doesn't support variable laser power with speed then it will happily set fire to the balsa with 100% and 600mm per minute the laser still hesitates, the laser is about twice as bright.

I think the underlying issue is that the processor can't process the gcode fast enough. I just wonder whether anyone else with the banggood laser has experienced this.

Martyn

06/04/2020 21:25:00

Apologies, that should have been 600mm per minute.

This is the problem with it slowing too much. There is a vid on YouTube https://youtu.be/b5-vxgoqpUI

What appears to happen is that it is pausing at each non linear curve start and stop rather than reading the data stream and processing it smoothly. But even the large wheel circles have not cut evenly. They have had 5 passes each and always pause at the same point.. However, the smaller wheel hub has cut perfectly. I thought it may be a USB problem but I am having the same issue on a more powerful and more modern system

dsc_1641.jpg

06/04/2020 17:01:17

It's a while since there has been a post on this thread. I am still plodding on but I have a couple of questions.

Software is Lightburn

The firmware on my LED Laser controller is grbl1.1h and it does indeed reduce laser power as it slows down for the bends.

However, the power reduction is too high. For example, I now need 5 passes as 600mm/sec at 100% power to cut through 1.5mm balsa. If I switch to the 1.1e driver, 100% power at 600mm/sec sets fire to the balsa on the first pass.

I would guess I am only running at 50% power. Drawing a circle doesn't even mark the wood as the power only seems to be about 25%. I cant see a way of increasing the power and wonder whether I have overlooked anything.

Any magic that I have overlooked?

I would welcome any suggestions, I am using a hell of a lot of wood trying to cut very few parts.

Thanks

Martyn

Thread: 7 meter ash 31 build
10/02/2020 16:53:56

Neck-ache, but that looks superb Roo

Very nice indeed

Martyn

Thread: Thermik Joe
07/02/2020 20:59:40

That looks great Bernd

Well done

Martyn

Thread: returning to bungee flying, big smiles
05/02/2020 14:53:19

Geoff

Have a look at F3-RES designs and perhaps have a go on the F3-RES postal league hosted on the BARCS forum

Sounds like it may be what you are looking for

Martyn

Thread: RAF's Finest Biplane? Hawker Fury MkI
04/02/2020 10:08:26

I agree, that looks lovely. Nice that its not standard Silver as well.

Not agricultural at all. Looks the business.

Martyn

Thread: MF's Hawker Fury Mk1
31/01/2020 22:15:28

That looks great Martin. We'll done. Beautiful work

Thread: Forum 2020 Mass Build discussion.
31/01/2020 22:13:21

My fan unit arrived. Nearly 6 weeks since I ordered it. Should be able to make a start soon

Martyn

Thread: AVIATION MODELER PIPER SUPER CUB
28/01/2020 10:45:36

I have a copy, can you PM me your email address please?

Thanks

Martyn

Thread: Thermik Joe
27/01/2020 16:23:28

That looks really nice Bernd. Love to know how it flies. Looks like it would make a great slope soarer

Thread: Antonov AN124 Ruslan
21/01/2020 09:06:14

I'll bet that with some tape over the seam, that would take off from a large puddle..

Looks amazing

Thread: DB Hurricane paint and finish.
20/01/2020 15:14:33

I have given up with all black aeroplanes. I find them a nightmare to try and sort out their orientation.

We used to colour Free Flight contest models all black - especially the undersides, Black maintains its colour 'depth' or density at a distance and in the murk. However - try and find an all black model on the ground after its blown over...

Martyn

Thread: 1/3 Fly Baby
20/01/2020 09:28:24

Love that colour scheme. I thought it was a fantasy scheme when i first saw it.

I was wrong. Beautiful

Well done

Martyn

Thread: I hope to assemble a laser cutter/engraver
18/01/2020 11:44:13

I know what you mean. Its a very strange way of operating. There were no lock nuts in my kit..

Thread: 7 Day challenge Nigel Hawes 30" Tucano...............
18/01/2020 11:42:37

Regarding the reading... Many years ago (about 30), as an up and coming young manager I was sent on a document assimilation course.. i.e. speed reading. Our instructor was a remarkable John Cleese double - although slightly shorter. We were shown how to take in (absorb) documents, one sentence, then a paragraph then a page at a time. Within 3 days my reading rate had gone from about 200 words per minute - which wasn't bad to 22,000 words a minute and I was understanding and remembering more. At the finale I read "3 men in a Boat" in 22 minutes and I can still remember discreet paragraphs of it now. We were tested on the book content - specifically events, names and places. It wasn't enjoyable reading and it was very hard work, headache inducing, but a useful skill to have.

I think I would prefer to build. Watching and good luck..

Martyn

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