Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
The tiny sandblaster turns out to be a Badger 260 with miniature Propel threaded fittings on the air line:
Badger Propel air fitting – DIY cork washers
Foreseeing a Propel washer getting lost in the confusion, I punched a few from a cork sheet and trimmed them to half-thickness. The little brass hole punch isn’t good for more than a few whacks, but that’s all I needed. My cork is crumblier than theirs, but I got a few decent-looking washers and, with a bit of luck, won’t need any of them.
Maybe I should make a soft gasket from a thin plastic sheet?
Most of the epoxy remains in good shape, but it’s obviously not the right hammer for this job.
Having recently spotted my tiny sandblaster, I think I can clear off the corrosion and epoxy well enough to try again with good old JB Weld epoxy. It’s not rated for underwater use, so I don’t expect long-term goodness, but it’ll be an interesting comparison.
Bonus: the slicer will start with a uniform gray surface!
The Mighty Thor provided the new-ish Squidwrench logo in various digital formats, not including DXF, but dxf2gcode can process PDF files (and a few others), and the cutting / weeding / transfer ended well:
MPCNC Vinyl Cutting – Squidwrench logo on mug
That’s the same 14 mil gold vinyl you saw in the Crown test.
Alas, I re-covered the pattern with the transfer film when I ran the mug through the dishwasher, in the mistaken belief the film would protect the vinyl. Come to find out the film adheres better to the vinyl than to the mug: it pulled loose during washing and peeled most of the logo off the mug.
Setting the drag knife to cut hot pink 9 mil = 0.25 mm vinyl film produced another logo:
SqWr logo – hot pink
It’s now survived several trips through the dishwasher with no protection, so I’ll call it a win.
I set dxf2gcode to use a cutting depth = 1.0 mm for about 400 g of downforce, which seems to work, although the vinyl surface showed some marks from the flat nose around the drag knife blade.
The USB camera provides a convenient way to set the “workpiece origin” before cutting:
bCNC – Video align
Because the camera sits 130 mm beyond the blade in the +Y direction, it can’t see the swathe along the front of the MPCNC. Hard and soft limits in bCNC / GRBL keep you (well, me) from smashing the gantry into the rails, but it’s a nuisance when you forget to tape the vinyl far enough from the front.
That’s a PNG converted from the SVG original, because WordPress regards SVG and DXF files as security risks.
Run the DXF through dxf2gcode (from the Ubuntu repository) to produce G-Code suitable for my MPCNC’s GRBL controller, tape a sheet of paper to a sacrificial acrylic sheet, fire up bCNC, set the origins, and run the G-Code:
First Paper Crown – test cut
As expected, the cut paper pulled off the acrylic, because it’s not glued down; I have some Cricut adhesive cutting mats which are definitely in the nature of fine tuning. In any event, the paper showed I could get from a DXF image to drag knife cutting action.
This being a crown, gaudy gold vinyl seemed appropriate:
First Vinyl Crown – weeding
The weeding process removes everything that’s not the crown; I used a razor knife to cut a square and remove the vinyl around the crown. A good needle-nose tweezer works wonders!
Apply transfer film to the weeded crown and peel it from its backing paper:
First Vinyl Crown – transfer film
Stick it on something desperately in need of decoration and peel off the transfer film:
MPCNC Vinyl Cutting – crown on mug
The tricky part is setting the drag knife cutting depth to match the vinyl sheet thickness (14 mil = 0.36 mm), so the blade cuts the vinyl without cutting through the backing paper. This seems best done with manual trial cuts on scrap vinyl, pressing the drag knife holder down firmly by hand and tweaking the depth adjustment for a clean cut.
The G-Code cuts at 400 mm/min = 6.7 mm/s, perhaps a bit on the slow side.
Most of the VBE variation comes from temperature differences: re-measuring the 2N3904 transistors with VBE ≅ 672 mV put them with their compadres at 677 mV.
The 2N3906 transistors have wider gain and VBE variations, so selecting a matched pair for the LM3909 current mirror makes sense.
The sheet inside the lid collects some essential parameters for ease of reference:
We’re riding home with groceries along Raymond Avenue, approaching the Vassar Main Gate roundabout, and, as is my custom, I’ve been pointing to the middle of the lane for maybe five seconds as I move leftward to take the lane:
Raymond Passing – Approach – 2018-10-04
The driver of HCX-1297 is having none of it:
Raymond Passing – Near Miss – 2018-10-04
The mirror passed maybe a foot away from my shoulder; I’d reeled my arm in as the front fender passed by.
All three traffic circles / roundabouts on Raymond neck the lane down and angle it rightward into the circle, which is supposed to “calm” traffic:
Raymond Passing – Roundabout – 2018-10-04
The design doesn’t allow much flinch room for cyclists and certainly isn’t calming for us.
The NYS engineer who designed the Raymond roundabouts said the whole thing was “standards compliant”, refused to go on a check ride with me to experience what it was like, and told me to detour through the Vassar campus if I felt endangered while sharing the road.
Obviously, NYS DOT personnel do not dogfood their “share the road” bicycle standards by riding bicycles.
This just in (clicky for more dots, but not clearer dots):
Spam image – xxx
Yes, the attachment was named xxx.jpg, presumably so I wouldn’t suspect it of containing anything untoward.
The name-dropping definitely adds verisimilitude: not just Microsoft (or Micro Soft) Windows and Google, but Yahoo, too. Be still, my heart!
It’s unclear how I would contact their “fiduciary agent in LIMA PERU” by dialing a 909 area code in California or sending an email to, um, eaaj@europe.com, but, hey, why not? Perhaps another version of me in a parallel universe used the Peruvian Internet?
This must be one of those scams where, if you’re bright enough to notice the problems, they won’t need to waste any time on you.
You’re welcome to my identification numbers. When you get the check, slip me maybe 100 large, preferably under the table, and we’ll call it square.
The Smell of Molten Projects in the Morning 