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Topics - ggallant571

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General Discussion / PLA breaking
« on: July 31, 2017, 05:32:09 PM »
I have two spools of Red PLA. Purchased about 3 years ago. Kept in sealed bag with some sort of moisture bag. One spool works great, the other typically breaks inside the extruder after about 30 minute. I have no problem trashing the bad spool but need another spool and no not wish to have a repeat performance. Bought the printer from Monoprice and was thinking I should order filament from them to be safe. Any thoughts ???

Custom Size Frames / core-xy
« on: July 31, 2017, 07:49:20 AM »
Based on the posts by pawpawpaw69 and others I have started a core-xy build. Have frame and first pass belt done. Has anyone determined the necessary belt tension?

General Discussion / 3d printer hotend problems
« on: July 13, 2017, 09:44:20 PM »
I recently purchased a Monoprice 3d printer. Believe the actual manufacturer is Wanhao. Have had very erratic results. I have suspected that the unit was running very hot as I had best results with PLA at 185C. Borrowed a thermal scanner from work and did some measurements. Both the hot bed and extruder were hot.

The bed was set at 50C and measured 78C.

The nozzle was set at 200C but was I unable to get a consistent reading. The displayed temperature was jumping from 170 to 215. The thermal blanket around the heat sink was smoking. Took it apart and noticed that the thermistor was hanging in air. Should have been in a cavity in the heat sink. I was getting better results with an enclosure.

Also, the heater element has a set screw to hold it in place but it was lose.

Time to order a spare set of hot end parts

General Discussion / Corner brackets
« on: July 04, 2017, 09:10:32 PM »
I am in need of enclosures for laser etcher and 3d printer. Lacking a table saw I decided to go cheap with 4.5mm foam board available at the local dollar store. Cut the sides and tried to hot glue the inside seam. With the help of printers tape the first box was assembled, ugly but functional. Decided to design and print corner brackets for the second box.

Attached is the openscad source file along with printable stl files. Built a test model with scrap foam board. The inner bracket gets tapped for a 3mm screw while the outer has a 3.2mm clearance hole. Plan on building full size tomorrow if I can get more panels.

General Discussion / raster to vector
« on: June 26, 2017, 10:02:32 AM »
I know this topic has come up before and solutions were posted but I am stuck. I have an image, Duck from "The Duck Song" that I etched for granddaughter. It etches nicely on the 100 x 100 mm slate tiles from Michaels. I used gimp to edit the raw image and savea at 254 dpi resolution. This then gets imported into my home brew Linux application for etching.

I want to create a jigsaw puzzle of the body parts in 2mm or  3mm soft foam. Figured I could accurately cut the same pattern in 5 different colors. Scramble the parts and keep the baby (and wife) active reassembling. Some of the parts, eyes and nostrils, might just get charred

Again using gimp, I created an outline that is typically 0.2 mm wide and did a test burn in raster more. Shape is there but the cut depth and width is very erratic. Used an online "png to svg" utility to convert to vectors. Inkscape reads and displays nicely. Problem is the dimensions are at approx 4000 x 11000 units. I have an A5 machine.

Tried scaling in inkscape. It reduces the image but not the overall canvas size. My host application will compensate for non (0,0) image offsets but there is some dimension that is still way outside the allowable A5 working size. Scaled the original png image and redid the conversion. Same resulting dimensions.

Thanks for reading!!!

3D Printer Software / 3D printer x/y steps per mm
« on: June 16, 2017, 05:26:32 PM »
I just looked at the motor conversion units on my 3D printer and X & Y are set at 81 while Z is 400. Since these device share components with the laser etchers I find this odd. Measured a 10x20x8 mm cube and it is long on all sides. Any comment?

General Discussion / Getting started with 3d printing
« on: June 11, 2017, 07:28:23 PM »
I purchased a Monoprice "Maker Select Plus 3D printer" and am not being very successful. Tonight I printed one of their sample files, a swan, that came out perfect. This was via the SD card. I then tied to replicate via Cura and USB from the host. Just strings that did not attach to the print bed. This was with black PLA. Tried again from sdcard with white PLA (printed better than black last week) and nothing. I think there is insufficient filament being pushed thru the nozzle. Also getting error messages on the Cura console that would hint at spelling mistakes in the code.

1. Is it necessary / feasible to clean the extruder?
2. Can the nozzle get clogged?
3. Do different clor filaments need different heat profiles?

Z Axis / Laser Beam Alignment
« on: March 02, 2017, 07:18:14 PM »
I have been using a not to precise home-brew z-axis mechanism. It is two vertical side plates with groves. A plate with a a nut on one side and the laser heat sink on the other moves up and down in the grove driven by a low power gear head stepper motor. The UP/DOWN accuracy is more than acceptable. However the slop in the slide causes the head to tilt. The error can be lessened by inserting a small spring. The total range is about 30mm but the typical usage has been less than 3mm.

BTW - this problem can exist on systems without the Z-Axis. Most wheel on V-Grove systems have significant wobble on the X laser carriage. Forcing the lower wheels up tight to the aluminum under frame can reduce it but eventually they become sloppy. Also, there is slop in the bolts used to attach the laser to the plate.

The is a another potential cause of mis-alignment, manually adjusting the focus lens. On my machine the focus dot has considerable variance in both X & Y. I do not know if this at an angle or not.

When doing single pass work such as etching it is probably a non-issue. When doing multipass cuts the effect is non-vertical edges and extra wide cut paths. I first observed this problem when cutting 20x20mm squares in 3mm plywood with 6 passes on a factory fresh machine.

The problem that I am trying to solve is implementing a laser alignment mechanism for both the X and the Y axis's. But first I need a method to measure the current angle. So far I have been cutting squares, examining the edges, adjusting, and recutting. Rather tedious but only needs to be performed after observing problems. The thicker the material, the easier it is to measure the alignment.

Currently thinking about mounting a 45 degree mirror on the top end of a rotating axle. To use:
  1. Position the laser at the center of the axle
  2. Emit a low power laser beam
  3. Measure the height of the laser beam at a known distance (~50mm)
  4. Rotate the axle 90 degrees and remeasure

If everything is perfect the heights should be equal. That is a big "if".

Other ideas:
  1. Use a t-square to align the beam with the base. Inject smoke to enhance the beam.
  2. Add leveling adjusters to the bed and using a level on the heat sink.
  3. Get a thick, easy to burn, non toxic, non-distorting foam material.
  4. Make the jig precise enough so that this becomes a non-issue.

Comments and collaborators wanted.

General Discussion / Murphy Lives Here
« on: February 22, 2017, 03:00:36 PM »
My A5 laser has been working great. Recently added homing switches, belt tensionors, and a G2 lens. Order of plate PCV arrived earlier this week and decided it was time to do the job I bought the laser for. The weather is great so I hauled laser, laptop, & plastic to garage so that I might survive the fumes.

Setup with laser near door, inserted card stock do do a test cut, and absolute crap motion. Checked the usual suspects like belts and wheels being tight. All OK. Back to basement for alternate poser supply and simple tools. No difference.

Went and got a stepper motor and it worked on all the stepper motor ports. No load by as expected. Checked the stepper current limits. OK. Switched out stepper drivers. No difference.

Plugged X axis into Y driver. Crap motion on X.

Disconnected Y belt and plugged Y motor into X driver. Works as expected.

Swapped y-motor power cable to x-motor and it works. Appears I have an intermittent open in the cable. Ohms out ok until I flex it. Ordered a bunch from ebay and I may have a beer or two or three and try find and fix the fault. 

Murphy is alive and well and I know his address!!!

General Discussion / Belt Tension Adjustors
« on: February 21, 2017, 01:08:36 PM »
I installed 3 sets of 3D printed belt tension adjusters on my A5 gig. Believe they were posted by user Beikeland about a month ago. The Y Axis went on in minutes, the X-Axis took a lot longer, mostly because I tried to do it in place and ended up disassembling just about everything.

It is necessary to cut the acrylic mounting plates to mount the belt to the holders. For the end plates I sawed the plastic the width of the v-grove from the top edge down to the 6mm hole. For the side plates I marked the location of the slot and used a drill press as a milling machine. Not very professional looking but functional.

Within seconds of installing the first y-axis clamp I was convinced these should have been mandatory from day one. Even without the adjustment screw mechanism the ability to place the belt in the holders was fantastic. No effort!!!!!

An unexpected benefit arouse in there is now an additional 1cm of range in both X & Y. Could be 2cm but I currently have limit switches in that space.

If I were to do it again:
  1. make the brackets slightly wider
  2. wider spacing between belt hold down screws
  3. change adjustment screw & nut from US 10-32 to 5mm
  4. smaller bore hole on adjustment screw
  5. uniform mounting holes to loose fitting 6mm.
  6. make out of solid gold.

BTW - They did not improve the quality of the burns, just made it much easier to get there.

General Discussion / Painters Tape
« on: February 16, 2017, 10:07:44 PM »
I purchased roll of Scotch blue painters tape in the 72mm (2.83 inch) width at Home Depot. Is there a magic formula for changing the laser intensity while etching? Do you etch twice, once for the tape and again for the wood?

General Discussion / Test pattern
« on: February 10, 2017, 03:40:10 PM »
I have been playing with etching slate. First 3 came out great, 4th was horrid. I don't think the laser can etch to the resolution specified in the image when working with slate. Test etches on neon colored card stock at very low laser intensities came out looking good. Wonder if the laser causes small explosions in the slate. As a result I hand generated 2 test pattern gcode files. One to hold the laser intensity constant and vary the speed. The other to vary the speed and hold the intensity constant. Turns out neither makes much difference in the slate. Also etched in wood and picture is attached along with source code.

General Discussion / Aligning laser beam
« on: January 30, 2017, 06:14:22 PM »
I have a home-brew Z-Axis. It helps when cutting 3mm plywood but I noticed that the cut was growing wider on each pass. Did some tests and determined that the beam is not exactly vertical, particularly in the X direction. Under an examination lamp, I can see that the slot is not vertical. Slopes the same direction on both sides.

Did the same cut without Z motion and it is much cleaner. Also played with the distance of the work to the lens and get the best cuts up close, 40mm vs 100mm.

I know the mechanism is not great but I have not idea how to align other than loosening, rotating slide, and tightening the screws, and reburning a line. Rev 2 of the z-axis is ready to be made but will hold off awaiting ideas on alignment

General Discussion / inkscape export
« on: January 18, 2017, 05:12:01 PM »
I have some files in svg format that I would like to convert to dxf. I open and display the files ok in Inkscape 0.91. Then I save as "dxf". The files get saved but the units are off. 10mm  exports as 2.82mm. The ratio is 3.54 which I recall is the pixel to mm at some standard ppi.

General Discussion / First Slate Etch
« on: January 08, 2017, 05:52:34 PM »
Tried my first etching in slate. Not very good compared to wood. Tried to etch the picture of a tigers head, assume I got it from this forum. The lines are nice and crisp but the texture of the hair came out all flat. I suspect it was a poor example to start with.

Going to try Agastar's Elf with text.

Is there a way to clean (sand) the slate so it can be reused? At least for test pattern.

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