Machinist
@Machinist@lemmy.world
- Comment on I need to vent about plastic milk jugs 1 week ago:
I actually think they’re correct. It explains most of it and jives with my experience.
The amount of plastic used is fixed. Here is a bottle blank I have for a 2 or 3 liter soft drink: Image
We’re assuming that milk jugs are blow molded from a similar blank at the bottling plant just before washing and filling.
Milk bottles are either High or Low Density Polyethylene. A notoriously elastic plastic. It also creeps all over with temperature, you can take a bowed 3" thick sheet of it, put it on the floor and it will usually be flat in the morning, especially if it’s above 75deg F or so.
Milk jugs aren’t a pressure vessel like soft drink bottles.
They’re saying that due to the large surface to volume ratio and thin walls, there is a lot of seasonal variation in final volume. This is primarily due to the compressed air used during blow mold, ain’t nobody paying to heat or cool it. Also, the ambient temps in the plant, in the blow mold area may see 40deg F swing, maybe more, over the course of a year. They aren’t going to pay to condition the air if it doesn’t affect final product. Fuck worker comfort.
This would be enough to show seasonal variation in milk level due to volume changes, especially since the jug necks up and exaggerates differences. Reduced headspace probably also keeps it fresh longer due to reduced oxygen. Mostly, if your competetior’s jug looks more full, you sell less milk. One producer does it, they all have to do it.
It’s a totally believable and logical explanation to me.
- Comment on I need to vent about plastic milk jugs 1 week ago:
That makes more sense. Nothing to do with wear. I guess the dimple would be a removable insert. You could have a selection of them and swap when calibrating the line.
I would think that blow mold is happening right before washing and bottling. Tube blanks are probably supplied in Gaylord’s coming from the plastic producer. Transporting semis full of empty jugs doesn’t make sense.
I’m suprised there is that much variation in volume, I would expect the temps to be more consistent. I guess the compressed air temp is the main variable, mold temps should be pretty consistent. Ambient air temp when the bottle is cooling probably also plays a role, more or less shrink before it “freezes”. Not sure if they’re made from LDPE or HDPE but those are both really stretchy, so I guess they very well could jump all over on size.
Most of my mold experience is in automotive, which is going to be a tighter process.
- Comment on I need to vent about plastic milk jugs 1 week ago:
I don’t think this is correct and would need to see a source before I believe it. I doubt the dimple is adjustable in the way you’re describing.
The amount of wear needed to change the volume by a noticable margin would be quite significant. Surface finish of the mold would be degraded enough that they would probably scrap the mold before using an adjustment like this as the mold would have sticking problems.
It might be volumetric compensation, but I doubt it’s directly wear related.
The mold is going to be at least two parts that split to get the blown jug out. The jug feedstock probably starts as a molded tube blank with the threads already in it. Would look like a test tube with a milk jug mouth.
Thinking about it, and I suppose you could actually call it wear compensation. Machine the mold with max dimple present. As your parting faces/lines take damage, you reface, and take some off the dimple to compensate for reduced volume. Maybe. That’s my best guess if it isn’t structual. Usually the rest of the mold has taken enough damage/wear that you’re scrapping the entire thing.
- Comment on Can I use your shower? 2 weeks ago:
Ah. Mistook the red pepper for a jar of instant coffee.
- Comment on Can I use your shower? 2 weeks ago:
I don’t know about the coffee and salad dressing, but, I totally keep a bottle of Ajax dish soap in the shower.
It’ll cut the gear oil off you.
- Comment on Sooo... This is happening on Imgur 3 weeks ago:
That tasty gif never gets old.
Boom! Knocked the fuck out.
- Comment on Accidental rapture 3 weeks ago:
I really like the interpretation of Cain and Abel having it’s roots in the transition from Hunter Gatherer to Agraian society. Gobekli Tepe and all that.
Another couple of fun ones are Christmas trees being forbidden in Jeremiah and cannabasam (forget where in the OT). I assume your uname is in reference to that cannabis use. The manna as psychedelic mushrooms is also a cool idea.
- Comment on Accidental rapture 3 weeks ago:
I like Cain and Abel/hunter gatherer vs agrarian theory.
The whole sons of god are angels having hybrid giant babies with human women is just a lot of fun.
- Comment on Accidental rapture 3 weeks ago:
Was raised in fundamentalism, lost my religion over a decade ago. (I’m cool with religious people that aren’t evil shitheads trying to brain wash children.)
You’re right about the snakes. Also, the plural tenses in Job are weird.
Not related to the post. What’s your take on the Nephillium?
- Comment on YSK about Project 100,000, when the US conscripted people with mental disabilities to be used as cannon fodder in Vietnam, suffering triple the casualties of other soldiers 4 weeks ago:
Little people were employed in the building and inspection of B-24s. Henry Ford Collection
Guess there’s some sort of truth to what I remember.
- Comment on YSK about Project 100,000, when the US conscripted people with mental disabilities to be used as cannon fodder in Vietnam, suffering triple the casualties of other soldiers 4 weeks ago:
Very possible it’s some crazy shit I was told as a kid. I’ll have to do some digging.
- Comment on YSK about Project 100,000, when the US conscripted people with mental disabilities to be used as cannon fodder in Vietnam, suffering triple the casualties of other soldiers 4 weeks ago:
Is this your first day on the left side of the interwebs? Atheists and agnostics are the norm. We’re mostly over it and not every shitty thing done is a direct religious issue.
Religion is just another control. Causes not symptoms.
- Comment on YSK about Project 100,000, when the US conscripted people with mental disabilities to be used as cannon fodder in Vietnam, suffering triple the casualties of other soldiers 4 weeks ago:
Didn’t they recruit little people to be aircraft mechanics in WWII? They could fit inside fuselages and wings?
- Comment on Standardization rule 1 month ago:
One Man, One Jar.
- Comment on Standardization rule 1 month ago:
This is fantastic! I didn’t know this standard existed.
New life goal is somehow getting this added to a production print.
- Comment on We all do this 1 month ago:
Not OP, but instrumental metal for working: Karma To Burn, Red Sparowes, Pelican (Pelican can feel a little souless but that’s my opinion).
- Comment on I feel like a buffet would fix this 1 month ago:
I agree with you. I still can’t make sense of it and I don’t understand how he is seen as having charisma. Even his voice is repulsive.
He’s so fake and slimy in his mannerisms.
Only thing I can figure is that many people just don’t perceive him this way and find him warm and personable.
- Comment on Antique Electro-Cautery Unit: Measuring voltage with ADC and general safety. 2 months ago:
I looked at the ZMPT101B, not sure if it will work at that low a voltage.
Did some quick looking at the ideal diode modules available on Amazon, but they were just schottky drop or so. Sparkfun had one that might work. Ideal diode is definitely the right sort of thing, just have to find one ideal enough. If I can find the right one, it should work.
I’ve been looking at precision rectifier op amp circuits. Even half wave gets me what I need.
- Comment on Antique Electro-Cautery Unit: Measuring voltage with ADC and general safety. 2 months ago:
That would be modern practice, wouldn’t it? It won’t affect operation at all and should be safer. Ground wire wasn’t really a thing when this was made.
I’ll be doing this.
- Submitted 2 months ago to askelectronics@discuss.tchncs.de | 6 comments
- Comment on CNC 2 months ago:
Porque no los dos?
I’ve found that subs really dig it when you’ve machined your own spanky tools…
Also, HAAS are some jank ass machines. Tiny ways, newer controls are glitter covered shit, they fucked up the remote handwheel…
- Comment on I'm blue ba da ba da dee da ba dieee 2 months ago:
Huh. I’m not sure how far back furries go.
If not, it’s certainly proto furry porn. Pretty sure it predates the formulation of Rule 34.
- Comment on I'm blue ba da ba da dee da ba dieee 2 months ago:
This was covered back in '93 on usenet. Behold: Smuckfest!
- Comment on American cops think they're what American firemen ARE. 2 months ago:
Might think about taking a break for a while. I have to, sometimes. Do some camping and mostly unplug. Anything real big goes down and you’ll hear about it.
Marathon, not a sprint. Fuck em, we’re harder. Country boy can survive.
- Comment on Won't you come 2 months ago:
That’s fantastic.
I’ve known a lot folks that talk like Boomhauer, (I’ve been told I do, as well.)
- Comment on Won't you come 2 months ago:
Black Hole Sun and Beavis and Butthead were both on MTV back then. I don’t remember if they watched the video on the show.
Anyhow, that video was up there with NIN’s Closer for general weird awesomness. The crazy smiles and expanding eyes are burned into my memory.
Also, proto Hank Hill on Beavis and Butthead.
I remember my grandfather being very upset about the “Beaver and Butthole” show.
- Comment on 2 months ago:
I very much agree. It is held up as this wonderful parable of how you should live. It’s the sort of thing that the powerful use to take advantage and abuse the weak.
This kind of puerile shit is bad for children and is just like a lot of the Jesus crap that gets pounded into kids.
- Comment on Should you copy a person's accent when pronouncing their name? 3 months ago:
He sounds like a pretty awesome dude. Thanks for sharing. Also sounds like he has you pretty well trained, he gets to ride and sniff.
We don’t have a small dog right now, our elderly Chihuahua reached the end a couple years ago and my wife is still raw.
- Comment on Can someone find a redeeming factor about this game? Like anything good about it. 3 months ago:
I never really figured out you had to drive as fast as possible and that the fuel level was actually a countdown timer. I was crazy about the cartoon and remember being so disappointed with the game.
- Comment on Should you copy a person's accent when pronouncing their name? 3 months ago:
That’s really funny to me. What was his name and what was he like?
