#garfield Logs

May 22 2022

12:10 AM rue_mohr: heh, apparently idle draw was 260mA so I bumped the charger up to 750mA
05:48 AM rue_mohr: polprog, 8051 or 8049?
05:51 AM polprog: 8051 :_
05:51 AM rue_mohr: cool
05:51 AM polprog: :) *
05:51 AM polprog: It's awesome
05:52 AM polprog: i posted some more pocs
05:52 AM polprog: pics*
05:52 AM polprog: https://twitter.com/polprogpl/status/1528323491577180161
05:55 AM rue_mohr: ah yea
05:56 AM rue_mohr: did they put an lcd driver chip on, or do someting really cool with the 8051?
05:56 AM rue_mohr: 8751
05:57 AM polprog: i think 8051 does the driving
05:58 AM polprog: good job on that cylinder, how did you seal it?
05:58 AM rue_mohr: O rings
05:58 AM rue_mohr: one at the base and one on the piston
05:58 AM rue_mohr: I didn't do anything to the 3d prints and I *THINK* they leak badly
06:01 AM polprog: yeah i guess they do
06:04 AM rue_mohr: 3:47am, gonna go to bed
06:04 AM polprog: gnight
06:06 AM rue_mohr: 2614
06:06 AM rue_mohr: I'm still waiting for it to drop
06:09 AM polprog: what is that number?
06:16 AM rue_mohr: 867-5309
06:17 AM rue_mohr: oh the twitter follower count
06:17 AM rue_mohr: I post it so I can work out if its still going up, or if its taken a drop
06:18 AM polprog: ah
06:18 AM rue_mohr: I'm kinda waiting for most of the people to realize they dont get what I do or something and unfollow me...
06:18 AM polprog: there is some webapp that tracks it for you
06:18 AM polprog: some strange guy i used to follow used to post the stats every week
06:22 AM rue_mohr: I can just never remember what the number was
06:22 AM polprog: just write it down every day
06:24 AM Tom_L: morning
06:25 AM rue_mohr: no no no, I'm definitly going to bed now
06:25 AM polprog: having some grain coffee (1pm)
06:25 AM polprog: yeah you should..
06:25 AM polprog: your tomorrow is sunday right? or monday
06:25 AM * polprog open(time.gov)
06:26 AM polprog: minus, so you still have 1 day of weekend left :D
06:27 AM Tom_L: i scared him off
06:28 AM * polprog sips grain coffee
06:28 AM polprog: i got one week left to finish the mechanical TV project
06:28 AM polprog: me and friends are making one for a fair at the uni
06:35 AM polprog: 2x2 cm, 20 lines
06:35 AM polprog: signal is 20px per line
06:35 AM polprog: It will receive an RTP stream
06:36 AM polprog: got two guys working on the mechanical part and im doing the electroncis
06:36 AM polprog: electronics*, designed a led driver (linear) which takes a pwm signal and integrates it
06:36 AM polprog: the integrator amplifier has gain and pedestal adjustments too
06:36 AM polprog: output goes to a mosfet driver
06:37 AM polprog: (mosfet is driven open loop though)
11:58 AM rue_mohr: surprised that a linear system wouldn't do better
11:59 AM rue_mohr: to get subsampled during the scanning, how fast is thepwm?
12:24 PM rue_mohr: yay, the death ray works!
12:52 PM Tom_L: now get the squirt gun to work
01:20 PM rue_mohr: pondering that, the drooling seems to be more of an issue I keep going back to
01:20 PM rue_mohr: in the shower I was pondering drilling out the nozzel and threading it
01:20 PM rue_mohr: I could thread in *things*
01:20 PM rue_mohr: like a little backpressure check
01:22 PM Tom_L: go for it
01:29 PM Tom_L: or smaller nozzle options..
01:29 PM rue_mohr: yea
01:29 PM rue_mohr: or extruders
01:30 PM rue_mohr: I'd just like to get it to work tho
01:30 PM rue_mohr: I think I'll try again, and go light on both temperatures
01:30 PM Tom_L: squirt it upside down
01:30 PM rue_mohr: ...
01:31 PM Tom_L: might be a trick
01:31 PM rue_mohr: I dont think the piston seals enough...
01:31 PM rue_mohr: oh, last night I did this...
01:32 PM Tom_L: last night i slept... i know you didn't :)
01:33 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1240120.jpg
01:33 PM rue_mohr: finished it about 3:30am
01:33 PM rue_mohr: I have some adjustments to make tho
01:33 PM Tom_L: what's it for?
01:34 PM Tom_L: steam engine?
01:34 PM Tom_L: pla may not take the heat
01:35 PM rue_mohr: pneumatic
01:35 PM rue_mohr: generic
01:35 PM Tom_L: that was the other thought
01:35 PM rue_mohr: a fellow in japan has been successfully making 3d printed pneumatic cylinders and valves with bits of metal pipe
01:35 PM Tom_L: brass piston arm?
01:35 PM rue_mohr: no, just steel
01:35 PM rue_mohr: the cylinder is copper pipe
01:35 PM Tom_L: looks kinda brassy
01:36 PM Tom_L: bak in a few
01:37 PM rue_mohr: I wonder where that colour is comming from...
01:37 PM rue_mohr: huh
02:44 PM rue_mohr: polprog, did you just double-post that?
02:45 PM polprog: Yeah im getting the hang of the crossposter
02:45 PM polprog: I removed the first post bc it had my name on the raspi label
02:45 PM polprog: Redrafted and edited it
02:46 PM polprog: Then the crossposted would not post it for 3 or so mins, so i deleted that and posted it again (i thought it does not post edited toots)
02:46 PM polprog: Its silly
02:46 PM rue_mohr: hah, you ever notice twitter hits you for deleting a post?
02:46 PM polprog: No?
02:46 PM polprog: never noticed
02:46 PM rue_mohr: doesn't propigate your following posts for a while
02:47 PM polprog: Interesting
05:37 PM rue_mohr: polprog, oh no!
05:37 PM rue_mohr: can you get another controller?
05:48 PM polprog: I guess ill have to get one from uni
05:49 PM polprog: Shame cause it was my own and i seem to have lost the other two...
05:58 PM rue_mohr: :/
06:05 PM polprog: Goodnight
06:05 PM polprog: Fucking mess.
06:05 PM rue_mohr: gnight
06:05 PM rue_mohr: things go wrong, its part of the process
06:05 PM rue_mohr: :(
06:07 PM rue_mohr: I can use tinfoil to barrier the plastic from the nozzel
06:23 PM Tom_L: won't tear?
06:23 PM rue_mohr: I can put a pinhole in it
06:24 PM Tom_L: guess i don't follow
06:24 PM rue_mohr: so the next two problems are holding everyrthing, and getting enough press force
06:24 PM rue_mohr: oh, I'll put a peice of tinfoil over the injection hole
06:24 PM rue_mohr: that way the platic wont ooze
06:24 PM rue_mohr: into the mold
06:24 PM rue_mohr: I think I can leave the nozzel up against the mold
06:25 PM rue_mohr: I'm not sure if I should try having the mold or the injector warmer
06:25 PM rue_mohr: but I think I need to coool it fast after its injected
06:25 PM rue_mohr: property of the PLA
06:25 PM Tom_L: mold less warm
06:25 PM Tom_L: it's like a 3 deg window isn't it?
06:26 PM rue_mohr: :/ yea
06:26 PM rue_mohr: it might work if I have the mold at like 60c
06:26 PM Tom_L: not optimum for injection molding
06:26 PM rue_mohr: and run the plastic a bit hot
06:26 PM rue_mohr: I'm kinda scared to try the other plastics
06:26 PM rue_mohr: but I ahve a LOT of pla to "burn"
06:27 PM Tom_L: they would certainly have different properties
06:27 PM rue_mohr: I'm also trying to understand cleaning out injection molders with polystyrene
06:27 PM rue_mohr: its reffered to a LOT
06:27 PM Tom_L: huh
06:27 PM rue_mohr: but I couldn't google anything about it
06:27 PM rue_mohr: it looks like it melts at 270c
06:28 PM rue_mohr: which seems WAY hotter than I'm used to for it
06:28 PM rue_mohr: I think the idea is that it can mix with the other plastics when heated, but will dissolve out with just about any chemical
06:30 PM Tom_L: this new office arrangement sucks
06:30 PM Tom_L: it's temporary... i hope
06:31 PM rue_mohr: I got an idea
06:31 PM rue_mohr: Tom_L, home office?
06:32 PM Tom_L: ya
06:32 PM rue_mohr: I got an idea, I can take a few hinges and make an xy swing arm to hold the injector
06:32 PM Tom_L: ice blasting
06:32 PM rue_mohr: mold!?
06:32 PM Tom_itx: https://www.youtube.com/watch?v=wYOWl3BuBJ0
06:33 PM Tom_itx: https://www.youtube.com/watch?v=35DPdOuao8I
06:33 PM rue_mohr: oh to clean it
06:33 PM rue_mohr: heh
06:33 PM rue_mohr: thought you meant your office space
06:33 PM Tom_L: that too for that matter
07:19 PM rue_shop3: ok, I'm putting 'keepers' in the seperation screw holes
08:05 PM rue_shop3: drat
08:05 PM rue_shop3: it slipped past the foil on me
08:07 PM Tom_L: runnin a test ehh?
08:20 PM rue_shop3: bad news, it didn't work
08:21 PM rue_shop3: another big mess
08:21 PM rue_shop3: BUT
09:14 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1240146.jpg
09:14 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1240147.jpg
09:14 PM rue_mohr: Tom_L, ^^^^^^
09:24 PM Tom_L: better!
09:25 PM Tom_L: looks like a few air pockets but it seemed to spread pretty even
09:25 PM Tom_L: surprised the antlers did as well as they did
09:26 PM Tom_L: does the eye look ok to you?
09:27 PM Tom_L: was it hard to get out of the mold this time?
09:28 PM Tom_L: looks like you need to clamp the mold too
09:29 PM Tom_L: cool..
09:47 PM rue_shop3: AND it cleaned the mold, its completely cleaned out now
09:47 PM rue_shop3: eye looks good
09:48 PM rue_shop3: yea, Im gonna have to give in on the clamp thing
09:48 PM rue_shop3: but oozing!
09:48 PM rue_shop3: problem
09:48 PM rue_shop3: I had a peice of wood ready to sit the nozzel on after I pulled out the mold
09:48 PM rue_shop3: oh and let me show you the support....
09:50 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1240148.jpg
09:50 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1240150.jpg
09:58 PM rue_mohr: do you think I can make a spring operated ball check to create backpressure? I dont know how far out from the heater I can get before the plastic cools off too much
09:59 PM rue_mohr: I might need to add air vents too, it looks like the plastic is sealing up between the plates
09:59 PM rue_mohr: it gets up into the seperation screw holes
10:09 PM Tom_L: put the screws in but not touching the other half
10:10 PM Tom_L: a hefty spring inside with a ball to check would work but it would get covered with plastic
10:10 PM Tom_L: the only way to clean it would be to reheat it i suppose
10:10 PM Tom_L: haven't thought of a good design for that yet
10:11 PM Tom_L: it wouldn't have to 100% seal.. just slow it down alot
10:12 PM Tom_L: https://www.toray.jp/plastics/en/amilan/technical/images/ami_tec_072.gif
10:12 PM Tom_L: https://d2n4wb9orp1vta.cloudfront.net/cms/0215ptNozzle5.jpg;mode=pad;width=1200;scale=up
10:16 PM Tom_L: https://alleycho.com/wp-content/uploads/2019/12/How-to-Check-the-Barrel-and-Ring-Wearing-of-Injection-Molding-Machine.png
10:16 PM Tom_L: that one looks interesting
10:17 PM Tom_L: only spring loaded instead of a screw
10:18 PM Tom_L: they all use a screw for injecting though
10:18 PM Tom_L: and feed pellets etc into the screw heating as it advances
10:18 PM rue_mohr: yes
10:19 PM rue_mohr: but
10:19 PM Tom_L: probably 100 different designs...
10:19 PM rue_mohr: the screw just loads the cylinder thats pressed by a ram
10:19 PM rue_mohr: they dont seem to show that
10:20 PM Tom_L: There are three types of nozzle tips based on their design in the injection molding process, including general-purpose, reverse taper, and free flow. The method of mold filling depends upon the creation of the nozzle tip and size.
10:20 PM rue_mohr: that lower left one has my interest
10:20 PM rue_mohr: free flow aint workin for me
10:20 PM Tom_L: hehe
10:21 PM Tom_L: you're 2nd attempt was a huge improvement though
10:21 PM Tom_L: hard to tell with all the colors but looks like it filled good except a few air pockets
10:22 PM rue_mohr: those aren't awesome diagrams
10:22 PM Tom_L: even the hanging ring
10:22 PM rue_mohr: yea
10:22 PM rue_mohr: I'm thrilled, esp cause it cleaned the mold
10:22 PM Tom_L: you think you're close on the temp?
10:22 PM Tom_L: :)
10:22 PM rue_mohr: yes, but I'm not sure what the mold was at
10:24 PM rue_mohr: I will need to start breaking down some of the other plastic
10:24 PM rue_mohr: I'll ponder this backpressure thing and try again
10:24 PM Tom_L: https://pro-plastics.com/tip-on-injection-molding-machine-nozzles/
10:28 PM rue_shop3: 29000 psi
10:29 PM Tom_L: some big molds
10:30 PM Tom_L: .. goin to sleep
10:48 PM rue_shop3: or awkward plastic
10:48 PM rue_shop3: I think bakealite is kinda crazy