Plastic Balls in Bearings?

[SillyOldDufferModerator @sillyoldduffer]

[SillyOldDufferModerator @sillyoldduffer]

Yesterday I was moaning to my sister about how rubbish most modern upright vacuum cleaners are. My whinge is they last about a year before losing efficiency due to multiple leaks around all the seals.

Sister told a tale of her handyman neighbour stripping down his Dyson and finding a ball-bearing made with plastic balls. Two questions:

1. Is it a misunderstanding or Fake News
2. If genuine, what's the advantage of using plastic balls in a bearing? Used properly plastic is a respectable engineering material, so it may not be for cheapness or planned obsolescence.

I half suspect this is fake news. I often pull my sister's leg over technical matters and – not for the first time – she may be taking her revenge.

Dave

[Wout Moerman 1Participant @woutmoerman1]

Maybe a ceramic bearing instead of metal. The white ceramic could be easily mistaken for plastic.

[John HaineParticipant @johnhaine32865]

Two thoughts.

Were they white? In which case it's possible they could have been ceramic, which are used in ball bearings for certain purposes.

Or, if your engineering spec includes low cost and a planned obsolescence, then using plastic balls could be a very sensible engineering approach!

[David JuppParticipant @davidjupp51506]

Plastic races with ceramic balls are used where water ingress is expected.

Metal races with ceramic balls are used in some high end bearings – amongst other advantages there is significant weight reduction.

[gerry maddenParticipant @gerrymadden53711]

Ceramic balls can be white or grey. But they are very light so could easily be mistaken for a plastic. I know that dyson has done some fantastic things with motor technology and he outstrips the traditional Japanese designs with speeds in the region of 100,000RPM. So he may well have determined that the benefits of light ceramic balls in terms of friction and being less demanding of lubrication are worth the extra cost.

Of course the 'plastic balls' may have been in a 'cheap n nasty' in the "turbo" head or something else less glamourous.

[Clive Brown 1Participant @clivebrown1]

Plastic balls are widely used for low friction bearings in marine applications, Torlon, a polyamide, is a common material.

Clive.

[Chris TriceParticipant @christrice43267]

I doubt very much Dyson are using expensive ceramic bearings when completely plastic ones are available and perfectly serviceable in this context. You can get them from MSC/J&L or RS. Their main advantage apart from being water corrosion proof is they don't need to be lubricated.

[Enough!Participant @enough]

Hard to imagine that plastic balls have the load-carrying capacity of steel balls.

[SillyOldDufferModerator @sillyoldduffer]

Well I never! Plastic bearings, whatever next?

Ceramic bearings are new to me too. Eye watering expensive, rounder balls, 30% harder than steel, 10 times working life, and lower rolling resistance! Those who insist on only the very best for their mini-lathe will soon be fitting them right left and centre. Bragging rights will be worth every penny!

Ta

Dave

[Chris TriceParticipant @christrice43267]

Posted by Bandersnatch on 24/02/2019 16:26:54:

Hard to imagine that plastic balls have the load-carrying capacity of steel balls.

Depends on their intended duty. For vacuum cleaner brush rollers or wheels etc, they'd be fine. We use them at the studio for mechanical suits if we need to keep the weight down for the actor.

Edited By Chris Trice on 24/02/2019 16:38:44

[Enough!Participant @enough]

Posted by Chris Trice on 24/02/2019 16:38:18:

Depends on their intended duty. For vacuum cleaner brush rollers or wheels etc, they'd be fine.

I'm surprised.

[Chris TriceParticipant @christrice43267]

Fourth item down:

https://www.mscdirect.com/industrialtools/plastic-ball-bearings.html

[Enough!Participant @enough]

Sorry Chris, I don't see that gives me any warmer feeling …. it's basically the same hyperbole as for all the bearings – they are trying to flog them after all.

It's just that the brush rollers seem to take such a beating that they wouldn't be the place to skimp. Weight and noise aren't serious considerations in that case either.

Edited By Bandersnatch on 24/02/2019 17:11:51

[Ron LadenParticipant @ronladen17547]

Posted by SillyOldDuffer on 24/02/2019 16:35:22:

Well I never! Plastic bearings, whatever next?

Ceramic bearings are new to me too. Eye watering expensive, rounder balls, 30% harder than steel, 10 times working life, and lower rolling resistance! Those who insist on only the very best for their mini-lathe will soon be fitting them right left and centre. Bragging rights will be worth every penny!

Ta

Dave

Dave,

Cost depends on the size, type etc, some of the special application ones and you need a second mortgage but you can also pay no more than the cost of an equivalent steel bearing. Some of the smaller sizes are really quite cheap, surprisingly so.

Ron

[LimpetParticipant @limpet]

They've been using plastic, ceramic and glass balls in bearings for the photo processing industry lfor years, ight loads and corrosive chemistry

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Limpet on 24/02/2019 18:49:49:

They've been using plastic, ceramic and glass balls in bearings for the photo processing industry lfor years, ight loads and corrosive chemistry

.

This guy has some interesting items: **LINK**

https://www.ebay.co.uk/itm/1-pair-Plastic-Bearings-Delrin-with-316ss-balls-Polypropylene-with-glass-balls/113597718247

… and he is a pleasure to deal with.

MichaelG.

[Max ToleranceParticipant @maxtolerance69251]

Plastic /acetal / polyamide Bearings have been used in engineering for at least the last thirty years to my knowledge. They are used in all sorts of consumer items including vacuum cleaners. Other users are washing machine manufacturers, computer printers, medical equipment, office machines, the car industry and probably a host of others too.

The advantages are cheapness, lightness and the ability to run without lubrication, they are also non rusting. There are companies who manufacture these in the same range of sizes as conventional bearings. Although they normally only cover the smaller sizes. They do not perform well in very highly stressed applications and of course for high temperature work. They can however run at very high speeds if used correctly.

The ceramic bearings mentioned in earlier postings are intended for extreme applications such as high temperature or where there are problems with lubrication etc. Typical uses are turbo chargers model jet engines etc. They are hideously expensive especially in larger sizes.

[Chris TriceParticipant @christrice43267]

Posted by Bandersnatch on 24/02/2019 17:09:31:

Sorry Chris, I don't see that gives me any warmer feeling …. it's basically the same hyperbole as for all the bearings – they are trying to flog them after all.

It's just that the brush rollers seem to take such a beating that they wouldn't be the place to skimp. Weight and noise aren't serious considerations in that case either.

Edited By Bandersnatch on 24/02/2019 17:11:51

Cost and maintenance free are though. Can't say I remember ever seeing metal ball races on the brush rollers of any vacuum cleaner so obviously not as big a beating as imagined. Actually I'd argue that if you're an older person dragging a vacuum cleaner up and down the stairs, weight is quite important.

[Enough!Participant @enough]

Posted by Chris Trice on 24/02/2019 19:48:35:

Posted by Bandersnatch on 24/02/2019 17:09:31:

It's just that the brush rollers seem to take such a beating that they wouldn't be the place to skimp. Weight and noise aren't serious considerations in that case either.

…..Actually I'd argue that if you're an older person dragging a vacuum cleaner up and down the stairs, weight is quite important.

You mean the difference in weight between plastic and metal roller brush bearings within the overall weight of the vacuum cleaner is noticeable/detectable?

[blowlampParticipant @blowlamp]

Posted by SillyOldDuffer on 24/02/2019 12:39:19:

Yesterday I was moaning to my sister about how rubbish most modern upright vacuum cleaners are. My whinge is they last about a year before losing efficiency due to multiple leaks around all the seals.

Sister told a tale of her handyman neighbour stripping down his Dyson and finding a ball-bearing made with plastic balls. Two questions:

1. Is it a misunderstanding or Fake News
2. If genuine, what's the advantage of using plastic balls in a bearing? Used properly plastic is a respectable engineering material, so it may not be for cheapness or planned obsolescence.

I half suspect this is fake news. I often pull my sister's leg over technical matters and – not for the first time – she may be taking her revenge.

Dave

Just get a Sebo.

Martin.

[FatgadgiParticipant @fatgadgi]

A few years back (cough, perhaps a lot) I was at a design course aimed at failure modes.

One of the problem examples was the classic – what is the worst failure a ball point pen could have. After many answers, the critical failure was deemed to be leaking because of the damage a 50p pen could cause to expensive bags and clothing.

As Chris said, plastic bearings don’t need lubrication. Neither do carpets, so perhaps he has it right.

BUT I definitely will never forgive two faced Mr Dyson putting electric vehicle manufacturing and his headquarters in Singapore !!!!

[Enough!Participant @enough]

Posted by Will Bells on 25/02/2019 00:07:22:

As Chris said, plastic bearings don’t need lubrication.

Sorry to belabour this but neither do sealed steel ball-bearings. Moreover, with the amount of dirt/dust kicking around the bearings should, necessarily, be sealed in either case.

My guess is that the only reason for plastic bearings for the brush rollers is a bottom-line somewhere.

[Chris TriceParticipant @christrice43267]

If both do the job and one is cheaper, which would you use?

[Enough!Participant @enough]

Posted by Chris Trice on 25/02/2019 01:04:01:

If both do the job and one is cheaper, which would you use?

 

By "do the job" do you mean equal (or better) reliability? If someone can come up with convincing reliability numbers (in this service) to prove that, then I'd use the cheaper one. I'd take a lot of convincing though particularly comparing a sealed steel bearing with an unsealed plastic one. It's also unlikely that the manufacturer looks at it in those terms ….. "is it cheaper and will it get us through the initial warranty period?"

Actually if I were replacing a bearing that had failed I'd go for the steel bearing anyway. The difference in cost between commercial grades of plastic and steel bearings is quite minimal as a replacement – and I'd certainly feel a whole lot better.

Edited By Bandersnatch on 25/02/2019 01:37:00

[Author]

Posts