I've got an idea for a little plastic item that will, I feel, be worth making commercially. It's about the size of a plastic teaspoon and needs to be made in flexible plastic about 1/8" or 3mm thick. Not having tried to do have anything like this made before I am, as usual, coming to this fount of all knowledge.
It is not possible to make a working prototype in anything but flexible plastic. Therefore I have to find an injection moulding firm that is able and indeed prepared to run off a small quantity (say 25) so that I can get them tried out by suitable people. This has not proved easy so far. Lots of "Sorry, not what we do" or just answer machines. I'd really like to have somewhere local so that (in a similar way to a recent project in wood), I can go and talk to them and sort out problems first hand.
Does anyone have any recommendations for a plastic injection moulding firm in, say, the Greater London area? One that is small enough to be interested in a small job but able to ramp up production if the item was successful?
Alternatively, Is there any simple machinery that I can buy that will allow me to make 25 prototypes in 3mm flexible plastic? One point - it can't be made out of a sheet of plastic, it really does have to be a moulding. I could make a non-flexible model of the thing out of Plasticene.
Ray L
Ray, cannot help with a moulder but I do know that the expensive part of injection moulding is the tooling. 25 or 2500 makes little difference with a small part, it's getting the tools made to do it. However, you might be able to get a prototype made using the laser/resin process direct from your CAD drawings. Not sure if there is a resin which turns out flexible though.
When I see my next door neighbour I'll pick his brains (Design engineer)
Hi Ray,
As Rob says the design and manufacture of the tooling will be an (expensive) fixed cost that you can't avoid if you are going down the injection moulding route.
Another way would be to get the parts hot formed and stamped out of plastic sheet, if the item's shape would allow that. This would need the plastic to be heated somewhat. And again some kind of tool/die will be required.
However, getting back to basics, your first task is to identify the loads, forces, temperatures, cycles etc that the item will have to survive during a reasonable working life. You'll also have to design for worst case scenarios eg someone deliberately bends it further than they really should.
So that takes you to what the physical dimensions of your item will be balanced against whatever plastic has the correct properties for the job.
Regarding the physical look and dimensions...well, to do it properly you'd need a Mechanical/Stress Engineer who could design the part on a computer and then carry out environmental tests on it. This is how a simple plastic teaspoon is designed ....remember it's got to cost next to nothing, be mass produced, be able to survive aggressive stirring in boiling liquid etc...so that teaspoon is actually a very sophisticated design.
There are 1000s of plastics out there but a good tool maker will probably have some useful advice on that front. He might also advise you on the best method of manufacture. Try Googling 'injection moulder london' to find a moulder...there's loads of results.
Yup, this is all getting a bit complex. So, it might initially be worth your while tracking down a Design Mechanical Engineer ( and I don't mean a car mechanic ;-)) and picking his brains. Or maybe even getting one of the London Uni's (eg Brunel) to take on the task as a project.
Please note that as soon as you tell anyone (and I do mean anyone) about your idea then they can scoot off and make it themselves...unless you have it patented.
If you need more, just ask.
Regards
Richard
Morning Plastics are quite close to you Ray, and might be worth a call. They could make/maintain the tool for you as well as produce the item. As mentioned above (and I'm sure you realised anyway) 99.99% of the cost will be in the non-recurring toolmaking. Production costs will be negligible. This means any business plan will depend critically on the likely volumes produced/sold.
Ray,
If you can get a set of CAD drawings of the item, you may be able to find somebody who has one of these:
http://reprap.org/bin/view/Main/WebHome
The project is aimed at home experimenters so there could be someone who would like a challenge producing something that may become important. As Rob says, it would be necessary to find a resin with the right properties but I'm sure there's an enthusiam to try something.
Steve
Magnificent! Once again this forum has revealed the broad knowledge-base of it's members (not something generally found in the world at large, it has to be said.).
Thanks for all your suggestions. The Reprap idea appeals but the thing I have in mind has a lot of curves, an orifice, and it curves back on itself - not the easiest thing to design using CAD even if I was CAD-trained (which I'm not). I didn't read absolutely every section of the Reprap website but it strikes me that to go with a 3D printer you need a 3D scanner that will produce the information that the 3D printer needs - then the science-fiction concept of a Replicator will really be a step closer.
The physical conditions my thing will have to endure are not particularly arduous - no extreme heat or cold, no immersion in fluids. The main thing is to show samples to a few of the right people because it's always more difficult to get people to understand an idea than it is to let them hold the thing in their hand and use it.
i'll check out Mooblies suggestion of Morning Plastics
Ray
Ray, if you think that this product is a winner I hope that you have it under a patent. At the moment it is only an idea so a firm could produce it.
Harry
A dental technician/ lab will make you a prototype, if you can supply them with a master. You could either model the master from clay or have it machined it from hard plastic or metal. The dental technician could then make a multi-piece plaster mould or a flexible mould from which to cast the prototypes. Dental labs have all the skills, kit and resins to make one off castings and plastic appliances.
Or if you want to save money you could do it yourself. You would get all the casting materials and resins from http://www.tiranti.co.uk/
Depending on what it actually is, and the size - this sound ideal for plastic printers. In case you've never heard of them, they're starting to be a hobby gone mad. The basic idea is you build a machine that actually makes things from plastic by melting a tiny thread of plastic and squirting it out like an ink jet printer - BUT the head stays static, and the work platform moves left/right, forwards/backwards, up and down. A friend of mine built one at Christmas and after finishing it started by building dice or sugar lump size plastic items. Then as he sorted the programming out, he started to make more complex things - the best one was a referee's whistle, that actually had a 'pea' inside and really worked. They take a while to produce the items, but could be just what you need. They link to a computer running CAD software. The weird thing is that you can actually make the parts of the machine - like the pulleys and guides, and then you sell these to the next people who are building one. Cost wise, the dental mould technique could be cheaper, but one day, these new fangled machines will take over!
Don't forget the ever so keen university departments and colleges that might want to help you out. Often at little cost if any at all.
See you on Dragon's Den soon then????
I know a keen dental technician in my village. She'd probably be happy to try if you want to ask her. Contact via me.
Alan,
As we live near-ish, that's an excellent suggestion. Today I'll be buying some Plasticene.
Thanks to all for your contributions.
Ray
Ray, you might want to investigate the slightly more high tech versions as seen here:
http://www.craftcellar.co.uk/contents/en-uk/d57_fimo.html?gclid=CKbb8trgo6ACFVAA4wodIDz4ZA
Plasticine is too changeable after you think you've finished. Fimo isn't perfect, but better and there appear to be loads of new variants since I last used it. (For animation!) I think you might find the odd sculpting tool useful too.
Ray, if this is serious, then I suggest we talk to Kate the dental technician round the corner. She has access to much more reliable materials than Plasticene.
If you want to consider a DIY solution I can give you details of articles describing construction of the 3D printer available in UK for £800 less 15% discount.
Alan.
How quickly things move on! Rob, quite independently my investigations in a craft shop yesterday revealed the potential of Fimo and I bought a block to do some trials.
Alan, I'll make a first trial in Fimo and get back to you. Once modelled to shape, Fimo can be baked into a rigid form. Not flexible like the intended object, of course, but more durable as a 'this is what it will look like' example.
Ray
OK, let me know what you want to do. I've not contacted Kate about it yet.
Can you share some pictures of items you made? where can i find some good free models to download i just begun repraping
Did this come to anything Ray?
After some trials, I reckoned that the idea had potential. The problem, however, was time. The idea had to have a low priority when matched against jobs which had deadlines (from getting the accounts finished to having a DVD ready for Christmas sales).
There's a neat concept in Len Deighton's novel Horse Under Water which I often use when categorising jobs. It is fiction, but is very applicable to everyday life.
"All jobs requested have R.I. codes and are then given D of C (Difficulty of Completion) codes. A low R.I. (i.e. not very important job) will be attended to if it gets a low D. of C. (i.e. it's easy to do). Similarly a high D. of C. requires a high R.I. to get it approved for action".
With a low R.I. and a high D.of C., my idea is having to wait in the queue (along with several others).
Does that mean you did . . . or didn't make a succesful small plastic item?
I didn't . . . . . . . but it's moving up the 'To Do' list