Sawing 40mm thick hard plastic...

[Winspear]

Hi all! New to this board with quite a specific question.
I am working primarily with CNC machine to make my products. I wish to work with a new material that is not available in sheets nearly thin enough that I need. It is incredibly expensive so lots of wastage from thicknessing is out of the question.

I came up with an idea to purchase blocks for example 100x100x40mm to cut into slices of 100mm x 40mm x (varying 2-8)mm to achieve thin sheets.
I haven't tried it yet but this is not really very good to do on the CNC. You lose the thickness of the cutter with each pass, and we are talking a LOT of money with this material. I found a source for a cutter that would be able to reach half the depth at 1.5mm width. That's still a lot of $$$ lost in 1.5mm extra each slice, and it would be an incredibly slow process of careful shallow passes, not to mention I would need to do two-sided machining to achieve the full depth. The cutters cost ~$50 and I can see myself breaking plenty, especially on a not-so professional slightly wobbly machine.

Anyway, enough of that. Seems the most logical plan is to saw. I do have a cheap scrollsaw which I was using to cut shapes freehand from similar plastics which are available in the sheet thicknesses I need. I've worked up to 8mm on these plastics but with the flimsy blades etc I can tell this 40mm job would be impossible. Of course, a scroll saw is no tool to use when I want to achieve a flat surface.

So - we are looking at circular table saws and band saws with a fence I guess. I should say I really know nothing about this stuff. The material is 40mm thick Ketron PEEK HPV. An incredibly hard plastic, though for perspective it is plenty softer than most metals I think.
Would most saws be able to handle this? What kind of blades am I looking at? Is it worth contacting local lumber yards regarding this as a service? If I'm going to buy something myself, how good and expensive does it need to be?

Thanks very much for any advice you can give! I did manage to hack of a slice of this stuff on my CNC today with an absolute bodge job and 3mm wastage - It's fantastic material and I can't wait to use it - the CNC is not an option unless I get that cutter and it will take hours to do even if I don't break it.

 

[Bluekingfisher]

I suspect your option would be to use a bandsaw, a scroll saw would probably not be a suitable machine for prolonged use on this material.

I am not familiar with the plastic you mention although most woodwork cutters can handle machining of plastic.....back in a mo, the fire building alarm has gone off....damn!

 

[Bluekingfisher]

Sorry, back now.

Eithyer way, there is going to be a fair amount of waste which ever way you slice the material. A table saw for example will hog out somewhere between 2.3 - 3mm of waste on each pass, while a bandsaw will take out around 1mm, depending on which blade you opt for.

I don't know if you have a bandsaw, however it is a very versatile machine, if space is tight then that would be the one machine to cater for most cutting solutions. the other benefit is, the foot print is not much greater should you have a small hobby or a machine capable of industrial cutting.

You will need a bandsaw with a motor of at least 1 - 1.5 HP. if you intend to do a lot of cutting The other issue which will be of concern is the quality of the blade guides and the usefulness of the fence if you are cutting such thin laminates. A good quality blade is also essential for such thin cutting.

There are plenty of decent quality second hand machines available for sale, something like a tried and trusted Startrite 352 for example may cost around £275 - £400 (ball park figure). Blades for such are around £12 - £15 (ball park) With regards to blades I would talk to the blade suppier and seek their guidance on the approipriate blade for the material to be cut. The type of blades available are wide and varied so seeking the right advice is crucial. There are a couple of suppliers the guys on here use and speak highly of them. I can't recall the supplier names off hand although I suspect someone will provide the details if you post the query, or try the search field on the top of this page.

Good luck with it and welcome to the forum.

David

 

[Phil Pascoe]

I can't see any kind of domestic machine giving you a cut of less that 1.5mm, but you could ring Ian at Tuffsaws to ask if he has any suggestions.

 

[Mark A]

I wasn't expecting prices like this http://www.plasticstockist.com/Ketron-P ... Plate.aspx :shock:

Just a thought... considering the material is so expensive, would laser or water jet cutting be an option (providing the plastic can be machined by those means)? I imagine the kerf would be considerably thinner than that of a table saw, or even a band saw.

 

[Phil Pascoe]

:shock: Drop that idea for my kitchen worktops, then.

 

[Random Orbital Bob]

It is clearly possible on a bandsaw but I would be inclined to have a serious chat with the manufacturers tek team before investing in any capital equipment. This stuff is quite specialised. Take the link below and read the pdf right through. It will give you an insight into how plastics behave with machine tools. Here is a short excerpt on bandsawing....so it is certainly possible with the right blades and precautions But you know I'm sure that the surface finish off a bandsaw won't be smooth.

http://www.plasticstockist.com/download ... ingins.pdf

For bandsaw blade requirements....talk to Ian John here: http://tuffsaws.co.uk/ He is the owner/manager of the best bandsaw blade company in the country and believe it or not he's also the best value for money. Literally everyone on this forum uses his services and he's got a wealth of technical knowledge on the correct blade for any given bandsaw application from butchery to wood to metal to plastics. He's your man. Contact details from his website. (I'm nothing to do with him by the way except being a happy customer).

 

[Bradshaw Joinery]

perhaps speak to a specialist plastics company like igus??

 

[woodfarmer]

I thought PTFE was expensive so used Acetal this stuff is not going to be used for bowl blanks

Would consider a metal cutting bandsaw as the low speeds will avoid any heat problems.

Ian at tuffsaws does do a range of "thin" blades but don't know how thin.

 

[Higon]

(As you may already know) If its one of the carbon fibre reinforced varieties of PEEK, then snapping the cutter is only one issue. The CF will dull / blunt the cutter very quickly. If you were designing a product to blunt cutters it would be a sandwich of MDF and CF. Then there's the 'dust'!

I'd go with a bandsaw and custom blade but be prepared to go through blades quite quickly, even Ian's excellent ones.

Is G10 no good for your application? It might be slightly cheaper, but only slightly!

 

[Winspear]

Thanks! This is all very helpful. I will look into bandsaws and contact Tuffsaws. If I can get 1.5mm I think I'm happy. I mean I'm still going to profit but with the prices so high you can see why I want to minimize wastage! This is expensive stuff indeed. I am aware this plastic is going to be a blade killer but the price of blades is negligible compared.
Laser cutting could be an option. I've emailed some companies but not heard back - I guess I may post on a laser forum to find out if that's an option.
Both a laser cutter and a band saw are on my long term shopping list after all!