The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

Tag: Laser Cutter

Juki / Arrow Sewing Table Insert Filler

Mary’s Juki TL-2010Q sewing machine sits in an Arrow Gidget II sewing table with a clear acrylic insert filling the opening:

Juki TL-2000Q in Gidget II table

Before the insert arrived (it had month of leadtime), I hacked out a temporary cardboard insert:

Juki temporary table insert

Although it may not be obvious from the picture, unlike my cardboard insert, the acrylic insert does not fill the tabletop hole to the immediate right of the machine:

Custom Inserts are U-shaped, designed to fit around all 3 sides of your sewing machine

Shortly after the insert arrived I hacked a temporary filler, for which no pictures survive, to keep pins / tools / whatever from falling to their doom. This turned out to be a blessing in disguise, because she wanted the machine positioned an inch to the right of its intended spot to leave enough space for a finger to reach the bobbin hatch latch.

I then promised to replace the ugly cardboard filler with a less awful acrylic filler and finally got it done:

Juki TL-2000Q in Gidget II table – insert filler

The stack of cardboard prototypes show iterative fit-and-finish improvements, with the odd shape on the top serving to measure the machine’s 25 mm corner radius by comparison with known circles.

The insert filler is made from smoked gray acrylic, because I have yet to unpack the acrylic stockpile and may not, in fact, have any clear 6 mm acrylic, so we’ll regard this as a final prototype pending further developments. It did, however, confirm the laser survived the move, which was pretty much the whole point.

The end of the machine is not a straight line. Part of the iteration was measuring the curve’s chord height to calculate the circle’s radius, which turned out to be 760 mm:

Juki Insert Filler – end chord circle

With that in hand, a few Boolean operations produced the filler shape:

Juki Insert Filler

A pair of silicone bumper feet stuck to the side of the Juki hold the left edge of the filler at the proper level.

For the record, the smoked acrylic came from a fragment of a Genuine IBM Printer stand I’ve had in the scrap pile since The Good Old Days:

Etsy listing – Vintage IBM Printer Stand

The LightBurn layout as an SVG image:

2024-05-08
Kenmore Microwave Turntable Drive Rollers

Our ancient Kenmore microwave has a three-armed turntable drive:

Kenmore Microwave – turntable installed

After all these years the (white) rollers have worn to the extent they fall off the (brown) drive arms all too easily. They ride in a recessed track in the glass plate that holds them in place during normal operation, but having once again found a roller wandering around when I put the turntable back in, it’s time for at least a temporary fix.

Everything is, of course, plastic:

Kenmore Microwave – turntable drive roller parts

I considered drilling the end of the axle and tapping it for a nylon screw + washer, but came to my senses just in time:

Kenmore Microwave – turntable drive

The laser-cut parchment paper disk (barely) fits over the axle against the outside of the roller, while allowing the hot-melt glue to glom onto the undercut and hold everything in place:

Kenmore Microwave – roller glopped

I expect the paper to wear / fall off in short order, but the HDPE roller won’t bind against the glue and the blob should remain latched in place for a while.

When those hideous glue blobs do fall off, I’ll reconsider drilling & tapping. More likely, I’ll just fire up the glue gun again.

Actual use required trimming the blob from the upper side of the roller / hub, because the track in the glass plate fits very close against the edge of the roller. The hideous glue blob slid freely on the roller, but jammed firmly against the plate, causing it to turn at half speed.

2024-05-06
Laser Cutter: Test Cuts

Just to see if all the laser parts once again fly in formation, I cut a defunct cotton shirt into shop wipes:

Laser cutter – first cuts after move

Which worked as before:

Laser cutter – more wipes

Not that I need more wipes, but in this case the process is more important than the product.

Looks like I can start using the laser cutter again … whew!

2024-05-02
Laser Cutter Alignment Check

A couple of test shots to verify the move hasn’t jostled the laser mirrors too far out of alignment:

Laser cutter alignment check

The overlapping scorches on the left happened at the Mirror 3 position with the laser head at the far left and near right positions. Not quite as accurate as immediately after I overhauled the beamline, but close enough.

The pair of dot + disk scorches on the right show the beam position on the platform at the focus point and 20 mm below. The red-dot pointer definitely traces a wavering path as the platform goes down, suggesting the leadscrews may have taken a sideways jolt during the laser’s trip down the basement stairs and are now distinctly angled in their guides, but it’s good enough for my simple needs.

Looks like the laser survived the move pretty much intact!

2024-05-01
OMTech Laser Cutter: Honeycomb Rivnut

The honeycomb platform in my OMTech laser cutter was secured by a pair of M4 screws passing through the surrounding frame into a pair of nuts requiring considerable contortion to install. As a result, I tended to use the screws as locating pins by just dropping them into the holes, which didn’t prevent me from jostling the honeycomb out of position on a few occasions.

With everything torn down as part of the move, I drilled out the holes in the frame and installed a pair of M4 rivnuts:

OMTech laser – Honeycomb screw rivnut

The scar around the hole in the honeycomb came from the factory; I have no idea what they were doing to cause that much wear.

Anyhow, installing the screws now requires zero contortionism and they locate the honeycomb much more securely.

I should conjure knobs for the top of the screws to eliminate the need for a hex key, although that’s definitely low on the task priority list.

Update: Like this:

Honeycomb screw knob

2024-04-30
Laser Water Chiller: Heating
The previous Basement Laboratory generally stayed above 60 °F = 15 °C, so I set the LightObject water chiller’s low-temperature alarm accordingly.

Having reached the point where I can set up the laser in its new home, I connected the chiller tubes, filled the reservoir with distilled water (and a squirt of algaecide), connected the alarm wiring, turned it on, and had the cool water trigger an alarm:

LightObject Laser chiller – low temp alarm

Which was relayed to the controller:

KT332N Diagnostic display – water protect active

Silencing the chiller’s alarm clears the error indicator in the controller, so it’s possible to Fire The Laser with too-cold water if necessary.

As with the previous icemaker chiller, plotting the water temperature as a function of time shows the pump adds some energy as it moves the water around the loop:

LightObject Q600 chiller – water heating

The gap in the data shows where I had a few other things to do, but the exponential rise is obvious. The chiller compressor starts at just over 21 °C and stops at just under 20 °C, so the exponential curve had gone about as far as it could go.

The numbers in the upper right of the plot give the weight of:
- An empty water bottle
- A full gallon bottle
- The partially empty bottle used to top off the reservoir
- How much water went into the chiller reservoir
The figures in the bottom mash the initial slope of that curve together with the weight of the water to find the 21 W required to heat the water at that rate, with a bank shot off British Thermal Units because why not.

A Kill-a-Watt meter shows the Q600 chiller draws 36 W with the pump running, which includes the controller and a column of blue LEDs behind the water level tube.

The pump (in the lower right) isn’t exactly water-cooled, but it’s not losing a lot of heat through that foam wrapper and maybe most of the heat really does come from the motor:

LightObject Laser chiller – right side internal view

The basement temperature will rise as Spring becomes Summer, so the chiller will start working right away, and it’ll definitely get more exercise when the laser starts cutting again.
2024-04-29
Sears Sewing Table: Foot Repair

While arranging the venerable Sears Sewing Table in its new abode, we found the casters underneath didn’t roll nearly as well as they should, which turned out to be due to an accumulation of damage:

Sears sewing table – torn MDF

As far as I can tell, all four casters have been displaced upward, probably because they have no support directly above their stems and any force applied to the wheel has plenty of lever arm against those screws.

The MDF panels on the outside of the table have pictures of wood laminated to their surface, but lack enough structural integrity to keep the screws in place. The plywood, however, survived largely unscathed, although the screws were pulling out.

I poked as much wood glue into the gaps as possible, then applied as many clamps as possible, with wood strips on both sides of the bulge squashing the MDF into a flat sheet. Over the course of two gluing sessions (I need more clamps!) spanning three days, while Mary really wanted to start sewing, the glue cured. I had plenty of time to unbend the brackets and put a more-or-less right angle between their two screw plates.

Rummaging in the box of laser scraps (after finding said box) produced disks cut from various projects that fit between the plywood bottom of the cabinet and the stems:

Sears sewing table – repaired foot – side

The brackets deliberately don’t match their original shape, because their new squareness put the screws into undamaged spots in the MDF and plywood:

Sears sewing table – repaired foot – bottom

The MDF will never be quite the same, but it’s flat on the visible side and the glue (seems to have) consolidated the fragments well enough.

Although those wheels look terrible, the bracket now holds the stem vertically and all four of them roll easily and pivot smoothly.

The laser-cut disks are held in place by pure faith and the overwhelming weight of all the MDF in the table, so they’re not going anywhere. Because the table’s weight now rests on the caster stems, as distributed across the plywood cabinet bottom through the disks, the brackets shouldn’t be subject to excessive upward force.

She started therapy right away:

Sears sewing table in use

And we continued moving in …

2024-04-08