Machinist @ Machinist @lemmy.world

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913

Joined

3 yr. ago

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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:

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.

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.

Woodchippers are four stroke. Most probably have a V-twin similar to a riding lawnmower.

You could totally hotrod the hell out of it, however. Just like racing gokarts, you could run nitrous or a turbo.

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.

I always enjoy his comments. I get the feeling he has spent a lot of time hearing stupid MAGAt shit and is totally over it.

It came as a demo with so many games. Finally played it a decade or so ago. It was pretty good.

If you don't already work in a trade, you'd likely have a bright future as a skilled blue collar worker. Your vocabulary would allow you to perform the deep magic.

I like to mention this when the subject comes up.

Late one night, slide under the truck with a 1/4" drill and a grease zerk fitting. Pop a hole in the muffler and screw in the fitting.

Using a grease gun, add the filling of your choice: silicone, tar roof patch, etc. Maybe add some canned tuna for fun.

Ah. Mistook the red pepper for a jar of instant coffee.

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.

"Chemical Irritant" - I'm guessing CS or tear gas. Scanned the article and didn't see it specified. Strange way to state things.

Note that use of CS and similar are banned under the Geneva Convention between armies. Used against civilians all the time by many governments.

There's the Perjury Trailer Queen we all love to hate.

That tasty gif never gets old.

Boom! Knocked the fuck out.

I mean, twenty gigs was more than anyone would ever be able to use.

Captain!

This sailor probably enjoyed your hospitality back in the day.

Thank you much!

That wasn't SOAD? What about the Metallica Imperial Stormtrooper march?

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.

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.

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?

Wife and five kids, definitely stressed about possible deporatation. Probably pretty fucked up from the war, 29. Shoots a couple of kids, 20 and 24. Fucking stupid shit. I just feel sorry for everbody.

Would be nice to know the real story.