This post could legit be posted in many forums but I picked this one because LW4 really enables this kind of tinkering.
I won’t disappoint you with a short post …
…BACKGROUND …
I recently discovered that my K40-S has some type of horizontal “jiggle” problem and while musing about what is wrong, I also realized the need for good testing patterns. Patterns that would verify machine movement, marking accuracy and resolution.
You already know that I have an addiction to solving K40 problems vs actually using one…
This jiggle problem … the solving of which creates another fascinating distraction that fits perfectly into my K40 obsession. That is, gain a better understanding of the design and performance limits of the K40, following with the science, engineering and tools to fix and improve. BTW: I am pretty sure my jiggle problem is loose belts but I have not fixed it yet because I want to verify these tools will diagnose this type of problem.
… Whats this got to do with IT! …
I decided to create a test pattern that would enable the simple but informative measurement of:
- mechanical movement in x & y
- optical resolution in x & y
- proper controller operation and performance
I was further motivated by my observation that we do not have a good and visual way to verify a K40’s total operation and performance after a conversion. We spend a lot of time in this forum trying to pinpoint problems. PWM is a classic case where machine-side power settings are confused with program side PWM settings.
Also motivating was the realization that to create this new tool I needed to gain pixel level knowledge of Inkscape/GIMP/LW4. One video from that adventure has already been posted.
OMG I needed to learn new tools to make new tools … NIRVANA!
…
Stealing from my laser printer engineering background I did my first pattern design and experiment this weekend.
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The pattern tool basics are described as thus:
- Designed in Inkscape at the pixel level with increasing line widths and spacing. Every line, every other line, 2 lines on/2 lines off, 3 lines on/3 lines off etc. Some vertical some horizontal all at 90 DPI. In aggregate this set of patterns should show all problems and maladjustment’s … I think.
- The patterns are labeled so we can refer to them while online troubleshooting
- Since the pattern is created as vectors it can be saved as both .svg and .jpg so that hybrid forms of the pattern can be created to test both vector and raster imaging. The same image can be vector drawn or laser scanned in the same job.
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Here is the cool part. LW4 allows you to load this file and then decide what, when and if a stroke/pattern/or raster is imaged. It will allow you to do this at the path level, meaning, you can set or change the marking order of each line on this test pattern. Also you can decide how much or how little of this pattern you mark for any given test. LW4 enables a test to position or duplicate this pattern anywhere in your defined work-space, useful to test perimeter effects of your optical alignment. Example: place of copy of this pattern in each corner of the work space.
Finally, after designing a test you can save your LW4 work-space to share or reuse. The test can also be saved and shared as g-code… just awesome!
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Does this really work on a K40!
Turns out that I was “hangout trouble shooting” a machine this weekend with someone while designing this pattern and testing it on my laser printer. I sent it to him for marking on his machine enabling a real time, real world test of this schema.
BTW: we were trying to figure out why the scan lines on this machine were not closed. With this test pattern we eliminated all the usual suspects and concluded that a small tweak on spot size and power was needed.
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The picts in order of appearance:
A. the source test pattern in image form
B. actual test pattern printed on K40
C. close up showing vertical gaps (on long pattern to the left). Laser spot and power needed adjustment. Did you know that the power in a laser spot is not linearly distributed (that another story).
D. Measuring placement accuracy. Tested OK!
E. Test photo using my phone shooting through the objective lens on a calibrated loop… wow that worked! Control sample is from my canon laser printer. I used that to test my source file.
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So, what do you think?
Z1. is this is a useful tool?
Z2. Any ideas on improvements
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If there is enough interest I will document its use and publish a finished source. Otherwise I will use it for my own K40 entertainment
