Turning plastic...managing the static electricity

implmex · Mar 23, 2021

Good morning All:
I'm turning some dirt simple ABS spacers.
The turning is easy, face the stock, drill and bore the stock, part off the stock rinse and repeat for 300 parts.
No issues there; under 10 seconds a part...all is going very well and I'm making decent coin.

Here's the problem:
The stringers are so damn static laden that they are hard to manage.
I'm violating every OSHA rule in existence on this job...door open, safety interlock disabled, hands in the work envelope, grabbing and pulling out the stringers as they form so they don't wrap on the tools or the job.
(BTW this is a gang chucker, so no 3000 lb turret whizzing inches from my hands with a porcupine of sharp tools sticking out ready to rip my paws off.)

Problem is they are sticking to me so I can't throw them into the trash bucket.
Also, the bucket gets so much static accumulating, the stringers just float right back out when I fling them in.

So by the end of 50 parts, I look like some hairy Neanderthal with black ABS stringers all over me, and they itch and tickle and drive me nuts...even worse than I already am!

I also get a nice ZAP every time I touch the lathe from all the static buildup.
Any solutions from the plastic turners among you?

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining

boslab · Mar 23, 2021

Unbunch a braided copper cable to earth touching the back of the rod, like a comb, sometimes helps if you don’t have a handy dandy source of gamma radiation lying about (don’t laugh that’s what gets used on blown film extrudes, a gamma source at the top of the tower, I got a job as a fitter mainly because of radioactive material registration with the NRPB, ended up packing carrier bags, lying twats)ABS has a weak positive charge btw not sure how that would help
Mark

CarlBoyd · Mar 23, 2021

Air Ionizer

No experience with static on a lathe, but ionizers work well for static control in other situations, I see no reason it won't work on a lathe.

And keep you hands out while it's running or you'll loose them.

CarlBoyd

AARONT · Mar 23, 2021

I haven't tried it, but you could try rubbing some dryer sheets on you and the tooling/machine. Or attaching them to your cutting tools in a way so the chips push past them. I don't know how long it would last but may be worth a shot.

toolsteel · Mar 23, 2021

very little to 0 experience with plastic....would a shot of coolant (DI water?) make a difference????
Maybe it would just make a mess?

BoxcarPete · Mar 23, 2021

toolsteel said:
very little to 0 experience with plastic....would a shot of coolant (DI water?) make a difference????
Maybe it would just make a mess?

DI water has all the ions removed so as to make it an insulator. Humidity matters, maybe you need to go even more aggressive with something like a mist, water with ions still in it. Are you running dry? It's possible that all this can be fixed with either mist or flood coolant.

jim rozen · Mar 23, 2021

To solve the static problem when you are removing the chips, keep a spray bottle of tap water handy and give them a shot or two from it. That problem will go away in the summertime.

camscan · Mar 23, 2021

Can you not break up the dwarf?

Mechanola · Mar 23, 2021

From my experience with plastics I know you can suck off a long string chip with a vacuum cleaner. On roughing I always go as aggressive as possible in order to produce short chips under a coolant flow, very little oil in tap water. To finish is trickier. Sometimes it helps to cut very slowly with a razor sharp tool. Pure water shower

implmex · Mar 23, 2021

Hi Camscan:
You wrote "Can you not break up the dwarf?"
Which dwarf did you want me to break up?

Isn't breaking up dwarves (or anybody else) considered to be unacceptable violence in a machine shop?

The problem with ABS is that the chips it makes are almost impossible to chip break.
If you push it too hard it just melts into a blob.
If you back off, out shoots a stringer.

It is possible to break up the swarf (which I assume you mean) by using a live tool instead of just single point turning, but it is a PITA to set up and now you have a bunch of staticky little maggots to deal with instead of staticky long stringers.
Ditto for running a slot through the part first so your chips can only be one circumference long.
They will stick like shit to a blanket too.

I am hoping for a brilliant solution from those who turn a lot of plastic...something simple and obvious.
Grounding the bar as boslab recommends has promise, watering the swarf has promise, but I'm really looking for someone to say "You idiot...just do........ I do this all the time and it works wonders against static when you're machining plastic on those cold dry days where you can suffer an electrocution just from taking off your sweater.
I'd even consider gamma irradiating myself as boslab also suggests, but that's hard on the cojones, and I still need them.

So please, please, all you plastics gurus out there...share your magic, solve my woes, make me blissful!

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining

HuFlungDung · Mar 23, 2021

I'd sure give the vacuum method a try, because you've still got a mess of chips to deal with, static charged or not.

DDoug · Mar 23, 2021

How can you be violating OSHA rules ?
Your location is "Canada"..... :popcorn:

MrStretch · Mar 23, 2021

Besides breaking the dwarfs, you might try wearing an ESD wrist band like those used in the electronics industry. The dwarfs are sticking to you not because you are irresistible but because you have an opposite charge?

DDoug · Mar 23, 2021

Static Eliminators - Products

implmex · Mar 23, 2021

Hi digger doug:
Good eye!
Yes I am in the Great Snowy North.
We have a bureaucracy up here that's just as evil, narrow minded, and stupid as OSHA can be...we call it "WorkSafe BC"
Same shit different pile.

I used the "OSHA" term only because it's instantly recognizable to the majority of the audience.

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining

Screwmachine · Mar 23, 2021

If you can get the chip to start up the vacuum nozzle you're gold, just don't break the chip! Goes right up like a spaghetti noodle. Once it starts to wrap, ugh. If you're having trouble with fine swarf try wiping things down with a dryer sheet.

mnl · Mar 23, 2021

Maybe an ionizer like one of these, but they may not have enough oomph to keep up with your budding van de Graaf generator. All you need is a pickup belt and you could be into serious lightning.

ESD Air Ionizers | Benchtop & Overhead Ionizer, Ionizing Guns & Nozzles - Correct Products

Scruffy887 · Mar 23, 2021

camscan said:
Can you not break up the dwarf?

Dwarf may get pissed. Be careful.

kustomizer · Mar 23, 2021

OMG, I forgot all about Snow White, now look at the can of snakes you just opened!!!!!!!!!!!

Scruffy887 · Mar 23, 2021

Vacuum cleaner with a grounded metal bin. My Shop Vac crapped out after 20 years and it had a Stainless Steel bin. On some plastic ( machine turns all plastic) parts we would sometimes hear a part get sucked down the hose. Stop and retrieve part from bin. But replacement vacuum has plastic bin. Open bin and reach in. SWARF ATTACK!!! All over hand and arm.

Turning plastic...managing the static electricity

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