6 Dec
2021
6 Dec
'21
8:22 a.m.
On Mon, Dec 6, 2021 at 9:42 AM David Bridgham via cctalk
<cctalk at classiccmp.org> wrote:
The inlays are mostly not done with any tools I have.
I do the graphics
with Inkscape. Rod made up the blanks with silk screening. Then I have
the white printing done at a printshop I found who has a large, flatbed
printer that can print white ink. I do have some ideas about how I
might try to make up blanks with a laser etcher I have access to but at
the moment we have an ample supply.
Cool.
Also, I've experimented with making my own bezels
out of PVC board from
Home Depot using a CNC router. In the pictures below, the yellowed
bezels are old DEC bezels while the white ones are ones I made. I
figured that if we ever get the QSIC shipping and people want indicator
panels (I hope they'll want indicator panels), I'd rather not depend on
them ripping apart old DEC bezels to make this work.
Yes. I'd rather not demolish my only indicator panel. I was planning
on demolishing a blank (I have a few short blanks, but most people do
not)
Anyway, I'd be most happy to have another person
with more tools to help
build bits and pieces of this stuff. I've noticed that as I gained
access to different tools, I came up with different ideas about how to
make things. I didn't think the laser etcher was all that useful until
I started using it.
I have a small 40W laser etcher that I essentially haven't used since
I have had access to large-format 80-120W laser cutters.
As for tools, I can rent a 4'x8' Shopbot router at our local
Makerspace that can turn out the light blocking bar or, from your
file, the frame. We also have a local company (IC3D) that makes
cubic-meter 3D Printers and makes their own filament from pellets,
keeping costs down. The founders are friends of mine and I've helped
repair sensors on their manufacturing line. If I had an STL, I could
get a bid on what it would take to 3D print one. It wouldn't be as
smooth as a machined PVC foam milled one, but it would be strong.
With a little post processing, a 3D Printed frame may give an adequate
look. Just a possibility. I haven't worked with PVC foam much but I
understand the principle.
Now I want to use it for everything. Turns out it
can't quite handle 3/8" Delrin; it just melts it and makes a mess.
That sounds like a power problem. Normally, Delrin lasers quite
nicely, at least at 80W. Thick stuff is hard in any printer because
of lenses, beam diffusion, etc. We sometimes have problems with 1/2"
material of any kind in ours. I've done some stuff in 2 passes, one
high, one low (refocusing/repositioning Z axis between job runs). We
also have multiple lenses for different focal points. One is only
good for etching/surface work, and one is good for cutting 3/8" and
thicker materials. We usually use the middle one since 99% of what
goes into our laser is 3-6mm stock.
Speaking of help, if anyone wants to review the QSIC
design, I'd welcome
that. This is by far the most complex circuit board I've ever designed.
I could take a look at it, I have some background in making Qbus and
Unibus interfaces, but how useful I'd be depends on what kind of
feedback you are looking for.
Back to indicator panels, here's a picture showing
a bit of the
evolution of my indicator panels...
http://pdp10.froghouse.org/qsic/indicator-panel-stack.jpg
... The only real thing I'd like to
change is the gloss. Somehow, DEC's inlay is as flat as flat can be.
I did notice that. I have no idea what to recommend. AFAIK, DEC just
used an acrylic with a specific surface texture. The only stuff I can
get is like what you have - smooth as window glass.
Cheers,
-ethan
