Author Topic: Progress, revelations and musings  (Read 14711 times)

PonoBill

  • Cortez Bank Status
  • *****
  • Posts: 25864
    • View Profile
Well, I sure didn't expect that...
« Reply #30 on: February 12, 2023, 05:06:54 PM »
Most of the stuff I've been printing has not precisely turned out to be dimensionally accurate. I know plastic shrinks a bit as it cools, and the printing process can create distortions, but I've been a bit surprised to find the major dimensions of my projects to be accurate, while the holes are universally hosed.

So I spent most of today working on calibrating stuff. No, I'm not a football fan.

The result has me a bit baffled. I expected some predictable percentage of shrink that I could compensate for. So I printed up a plate with holes that I dimensioned in millimeters. Printed one in Polycarbonate, which is one of the most vilified filaments for shrinking and warping, and then measured each hole. I expected some sort of percentage of shrink that I could use as a compensation multiplier. And instead I got this:

Note that I somehow skipped 9mm in making the plate. It basically looks like each hole is roughly .2mm smaller than it should be. I'm baffled.
« Last Edit: February 12, 2023, 05:10:37 PM by PonoBill »
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

surfcowboy

  • Cortez Bank Status
  • *****
  • Posts: 4929
    • View Profile
Re: Progress, revelations and musings
« Reply #31 on: March 21, 2023, 10:32:49 PM »
I cannot fathom why this isn't linear.

PonoBill

  • Cortez Bank Status
  • *****
  • Posts: 25864
    • View Profile
Re: Progress, revelations and musings
« Reply #32 on: March 22, 2023, 08:24:01 AM »
Heat and moisture, perhaps. There's no control over the temperature in the printing chamber, and the filaments I'm using are hygroscopic. Printing them in Maui (or Bora Bora as Admin likes to call it) is challenging. I'm modifying my Bambu Labs printer to control both.

For the chamber, I'm adding insulation and a thermostatically controlled heater. I'm not going to heat it as much as I can--there are electronics, motors, drive belts, and plastic support parts in or around the chamber. But if it's insulated and heated I can control the temperature at a somewhat higher temperature that won't start making things more complicated rather than less. That means less part warping, better adhesion between the layers, and better tuning. It also means problems with overhangs and shallow angles since the part cooling won't be as effective for keeping bridged and angled areas from slumping. But that's solvable with part design and support. And I can turn it off if I want to print garden gnomes or LOTR figurines.

Drying the filament is a bit trickier. I'm converting the lovely AMS (automatic material selector) that holds four spools of filament and delivers filament according to the print program into a hacked filament dryer. Most folks dry filament by heating it in a oven at 100C for a few hours. That's fine if you live in Arizona, but in Bora Bora, or Oregon in the summer I want something more consistent. I'm building a filament dryer that pumps warm dry air through the sealed box of the AMS continuously. I prototyped a simple version of this using two forced air PTC(positive temperature coefficient) heaters that push warm air into the AMS, then recirculate it back through a desiccant bed. As soon as I get back to Hood River I'll start printing the final version, which adds a regenerative Peltier dehumidifier that puts a cold heat sink in the path of the air returning from the AMS, condenses out the humidity, rewarms the air by running it over the hot side of the Peltier plate, then shoves it into the desiccant bed. I considered adding heating elements to automatically restore the desiccant, but that drives moisture out of the desiccant, so it wouldn't be all that rational. And this is probably complicated enough. I know that all sounds expensive but it's actually going to be about a hundred bucks in parts--thank you China--and some 3D-printed PLA parts. The design is the expensive part, and that idiot works for free.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

PonoBill

  • Cortez Bank Status
  • *****
  • Posts: 25864
    • View Profile
Re: Progress, revelations and musings
« Reply #33 on: March 23, 2023, 07:47:28 PM »
Back in Hood River. It's nice to get back in my shop but Jeez it's cold! I saw someone paddling a downwind board at the event center and I absolutely had no interest in joining him. Could someone call me when the air temperature hits 80 and the water temp hits 70? I'll be huddled by the fire until then.

Diane and I get to spend way too much time with Docs this year. She's getting both knees replaced, I'm getting an ablation to extend this AFIB-free streak. I'm blaming Amiodarone for my recent weight gain. My cardiologist is skeptical. He thinks it's all the food I ate.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

Badger

  • Cortez Bank Status
  • *****
  • Posts: 2662
  • Seacoast NH
    • View Profile
Re: Progress, revelations and musings
« Reply #34 on: March 24, 2023, 07:26:36 AM »
Diane and I get to spend way too much time with Docs this year. She's getting both knees replaced, I'm getting an ablation to extend this AFIB-free streak. I'm blaming Amiodarone for my recent weight gain. My cardiologist is skeptical. He thinks it's all the food I ate.

I had an ablation last July and have been AFIB-free ever since. I had a few mild TIA episodes in August so the surgeon is keeping me on Eloquis just to be safe. He is suggesting I get a Watchman implant but I'm holding off on that for now. In 2022 I had an ablation, an emergency appendectomy, and an inguinal hernia repair among other things. I don't want any more procedures for a while.
Kalama E3 6'1 x 23" 105L
Axis HPS 980 / PNG 1300
Sunova Flow  8'10 X 31"  119L
Me - 6'0" - 165lbs - 66yo

Admin

  • Administrator
  • Cortez Bank Status
  • *****
  • Posts: 6443
    • View Profile
    • StandUpZone
    • Email
Re: Progress, revelations and musings
« Reply #35 on: March 25, 2023, 01:21:49 AM »
Back in Hood River. It's nice to get back in my shop but Jeez it's cold! I saw someone paddling a downwind board at the event center and I absolutely had no interest in joining him. Could someone call me when the air temperature hits 80 and the water temp hits 70? I'll be huddled by the fire until then.

I thought I would be in by now for sure but...42 degree water (and air) doesn't sound inviting for proning.  On the upside, we are just back from Arizona and Southern California and both were cool as well. :)

Beasho

  • Cortez Bank Status
  • *****
  • Posts: 3224
    • View Profile
Re: Progress, revelations and musings
« Reply #36 on: March 25, 2023, 05:42:10 AM »
Back in Hood River. It's nice to get back in my shop but Jeez it's cold! I saw someone paddling a downwind board at the event center and I absolutely had no interest in joining him. Could someone call me when the air temperature hits 80 and the water temp hits 70? I'll be huddled by the fire until then.

Not to get all personal but why would you leave Maui for Hood River in March?

My version of this would be leaving Mavericks in February to go to the Ice storms of Eastern Connecticut. 

PonoBill

  • Cortez Bank Status
  • *****
  • Posts: 25864
    • View Profile
Re: Progress, revelations and musings
« Reply #37 on: March 25, 2023, 08:40:20 AM »
Came back early to get Diane's knees replaced--one about a week from now, the second in September. The things we do for love.

Then again, I have a few thousand projects going at my shop. It will be nice to finish one or two.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

Admin

  • Administrator
  • Cortez Bank Status
  • *****
  • Posts: 6443
    • View Profile
    • StandUpZone
    • Email
Re: Progress, revelations and musings
« Reply #38 on: March 27, 2023, 11:18:49 AM »
Bill, Do you have any of the ART foils with you?  I want to grab some profiles (airfoils, I suppose) off of those.  I have done about 20 foils so far but I have never actually seen an ART in person and I want to see what they are doing.  It will only take me a half hour to get root, mid and tip profiles. 

jondrums

  • Peahi Status
  • *****
  • Posts: 894
    • View Profile
Re: Progress, revelations and musings
« Reply #39 on: March 27, 2023, 03:12:46 PM »
Admin - how are you extracting the foil sections?  I did it before with paper but it took longer than 20 minutes all told

Admin

  • Administrator
  • Cortez Bank Status
  • *****
  • Posts: 6443
    • View Profile
    • StandUpZone
    • Email
Re: Progress, revelations and musings
« Reply #40 on: March 27, 2023, 05:34:59 PM »
Admin - how are you extracting the foil sections?  I did it before with paper but it took longer than 20 minutes all told

I am using a Revopoint Mini scanner. It works really well for this but the scan spray and very particular lighting is required.  It took me a while to get used to it and I hate the software but it is very quick and accurate now.

PS, I remember that thread and it was super helpful.  It got me started on looking at (and comparing) wing profiles.  Great to have a reference to things that you have liked and disliked.  I tried both the wire method and the contour tool.  Both were OK for getting a rough idea but there was not a lot of confidence there for me, especially when trying to measure and digitize. 
« Last Edit: March 28, 2023, 01:38:07 AM by Admin »

PonoBill

  • Cortez Bank Status
  • *****
  • Posts: 25864
    • View Profile
Re: Progress, revelations and musings
« Reply #41 on: March 27, 2023, 08:53:34 PM »
Bill, Do you have any of the ART foils with you?  I want to grab some profiles (airfoils, I suppose) off of those.  I have done about 20 foils so far but I have never actually seen an ART in person and I want to see what they are doing.  It will only take me a half hour to get root, mid and tip profiles.

Yeah, I've got my 999. I'll come by this week. Tomorrow I have to take Diane to PDX for a presurgery appointment, but probably Wednesday. I fucked my afternoon up today by having to spend most of it in the ER. I was doing some modifications to my motorcycle trailer and leaned on the high end of the seesaw. Of course, it went down, I lost my balance trying to make sure it didn't hit Diane's Tesla and wound up face planting in the trailer frame. Steel is hard, faces aren't. No real damage, I wasn't pretty to start with, just some bumps and scrapes but they gave me a CT scan to make sure I wasn't bleeding out in my giant gourd. I'm on anticoagulants because of the AFIB that I don't currently have, so that added to the drama--and the gore. It looked horrible, as all scalp and forehead cuts do, but really wasn't that bad.

I never quit whistling.
« Last Edit: March 27, 2023, 08:58:37 PM by PonoBill »
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

Admin

  • Administrator
  • Cortez Bank Status
  • *****
  • Posts: 6443
    • View Profile
    • StandUpZone
    • Email
Re: Progress, revelations and musings
« Reply #42 on: March 28, 2023, 01:01:28 AM »
Honestly, you would need to have also suffered some electrical burns and an organ removal for this to make the Babcock top ten. 

Bills Obit: 

Bill Babcock
Some Dates
He was Durable

Heal up buddy.  Stoked that you lived (and have the wing).  Wed later afternoon is great or next week (I can stop by the shop as well).  No rush at all.  I am just curious.

PonoBill

  • Cortez Bank Status
  • *****
  • Posts: 25864
    • View Profile
Re: Progress, revelations and musings
« Reply #43 on: March 28, 2023, 07:25:36 AM »
The shiner is a late addition but adds to the drama. I didn't hit my eye, but now we know where that goose egg drained, eh?

 
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

Admin

  • Administrator
  • Cortez Bank Status
  • *****
  • Posts: 6443
    • View Profile
    • StandUpZone
    • Email
Re: Progress, revelations and musings
« Reply #44 on: March 28, 2023, 09:12:25 AM »
The shiner is a late addition but adds to the drama. I didn't hit my eye, but now we know where that goose egg drained, eh?

In my best Quint, "but we delivered the bomb" voice:

But he saved the Tesla.

 


SimplePortal 2.3.7 © 2008-2024, SimplePortal