What they used was much more simple. A reel of film on one side of the mold, and a take up reel on the other side. When the mold opened the takeup reel advanced the film. The "good" side of the film faced the finished side of the mold cavity and the injected plastic forced it against the cavity. Crude but did the job needed.

That's called IMD (In-mold-decoration). There is a new version now where the mold grabs the film a heater is inserted between the two halves of the mold to heat the film, film is vacuum formed to one half of the mold cavity, then the resin is injected. The image from the film is transferral to the molded part.

 

I'm not sure your going to get the results you think you will. Just the blowing of the air will probably make new static in a closed area like a box car. It's probably going to take a pressure washer type thing to remove the plastic dust. One that uses something on the order of clothes washing or dryer sheet anti-static chemical added to the water. Static and plastic are great friends, so it takes something else to break the bonding.

The blowgun at the plastics plant only worked or was helped by the air curtain blowing the paticals down toward the floor when in use. I forgot that when first answering it was many many years ago(late 70's) and a couple of strokes ago.

We will see. It is an experiment to see if we can improve upon a process that already works with compressed air alone.

 

I have a suspicion that high velocity air can cause ionisation. The only reference I can find to this effect is here.

 

I have a suspicion that high velocity air can cause ionisation. The only reference I can find to this effect is here.

- Did you read the paper?

...and the title?​

"Ionization of air in flow around a blunt wedge at relatively low hypersonic speeds"​

- Do we know what hypersonic means?
Note: Even "relatively low hypersonic" is still hypersonic.

If the only reference of flowing air to generate ionization of a surface includes "relatively low hypersonic speeds", then I can assume virtually no way the nozzle at the end of the maintenance departments air hose was randomly designed to supply air at hypersonic speeds - and no chance to ionize a surface with the air hose used to blast out a box of plastic pellets.

Note2: from Wikipedia... "In aerodynamics, a hypersonic speed is one that exceeds 5 times the speed of sound, often stated as starting at speeds of Mach 5 and above.[1]"

 

- Did you read the paper?

...and the title?​

"Ionization of air in flow around a blunt wedge at relatively low hypersonic speeds"​

- Do we know what hypersonic means?
Note: Even "relatively low hypersonic" is still hypersonic.

If the only reference of flowing air to generate ionization of a surface includes "relatively low hypersonic speeds", then I can assume virtually no way the nozzle at the end of the maintenance departments air hose was randomly designed to supply air at hypersonic speeds - and no chance to ionize a surface with the air hose used to blast out a box of plastic pellets.

Note2: from Wikipedia... "In aerodynamics, a hypersonic speed is one that exceeds 5 times the speed of sound, often stated as starting at speeds of Mach 5 and above.[1]"

We also have thunderstorms where the movement of air at lower speeds generates very large static voltages.

 

We also have thunderstorms where the movement of air at lower speeds generates very large static voltages.

The movement of air doesn't cause the static buildup (although that was a theory about 40-years ago - and more). The current widely accepted theory is that warmer but still super-cooled water droplets and snow rising from lower levels in the cloud collide with the larger, colder hail or sleet that is falling (or held suspended in the updraft). The collision causes a negative charge on the suspended/falling hail/sleet and a positive charge on the rising snow/super-cooled water.

The slow moving air alone does not generate or hold a charge.

Maybe a quick Google search will help you...
https://www.weather.gov/safety/lightning-science-electrification

 

We also have thunderstorms where the movement of air at lower speeds generates very large static voltages.

What I read in the process of researching all this, is that the static charge in thunderstorms comes from the collision of water droplets moving around inside the cloud. Also evaporation causes it.

 

What I read in the process of researching all this, is that the static charge in thunderstorms comes from the collision of water droplets moving around inside the cloud. Also evaporation causes it.

Wind passing the blades of wind turbines generates a static charge on the blades.
https://ieeexplore.ieee.org/document/8702878

 

it's pretty well established that the static on wind turbine blades is caused by dust/sleet eroding the paint or epoxy/fiberglass composite on the blade. Static is generated when a molecule is torn apart by friction/abrasion - especially polymers. Like balloon + hair, lanolin plus wool (using the friction of a glass rod), socks on nylon carpeting, or you can directly charge the glass of a CRT and watch it collect charged dust particles.

im not sure how you want to damage a polymer on a surface with pure air unless you have a surface that can be formed to create an enormous drag coefficient with air or easily break in a jet of slow air (like an expanded polystyrene packaging peanut).

 

Wind passing the blades of wind turbines generates a static charge on the blades.
https://ieeexplore.ieee.org/document/8702878

Interesting, I have never heard of this.

 

Would that be what causes cancer when you live near a wind turbine?
https://www.usatoday.com/story/news...ent-donald-trump-claim-blown-away/3352175002/

No, I think wind turbines cause cancer by a different mode - stress. For example, when you spend millions and millions on a Golf Course on the Scottish coast and then a power company builds some wind turbines just off shore, you might get really stressed that nobody wants to join your country club because the wind turbines are "ugly".

Maybe he didn't mean wind turbines caused actual cancer. He may have meant the kind of "cancer" that was discussed by some intolerant people when certain people or businesses moved into a neighborhood.

https://www.bbc.com/news/uk-scotland-north-east-orkney-shetland-47400641