Compression/stretching of filament in bowden extruder?

Hi All

I am looking at putting a Bowden extruder on my printer. I have sourced 1/8x1/4 PTFE tube (id = 3.2mm) and was wondering if given my PLA is 2.9mm whether I should rather go for 3mm ID tube.

Really, is the stretching/compression of the PLA (and hopefully later ABS) noticeable over 0.5m perhaps? Or would it be negligable compared to the stretching of the bowden cable itself?

Cheers for any advice.

Let's suppose you want to deposit 0.5mm filament with an accuracy of half the filament width (quite poor compared to 0.1mm target resolution). The resolution of the drive needs to be 0.25 / 36 = 7 um. Any plastic will stretch more than 7um over 0.5m when subjected to something like 50N.

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[www.hydraraptor.blogspot.com]

Hi

Do you have a source for small quantities of PTFE tube in the UK?

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Regards

Ian

Hi Ian,

Adtech are based in Gloucestershire - Adtech PTFE Tube

Tube Sizes

Cheers,

Rich.

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[richrap.blogspot.com]

I purchased 1.5m of 1/8x14 (or 3.2mm ID by 6.xx mm OD) @ £6.?? per meter. They had a 1.5m offcut so I did not have to pay the £10 small order surcharge (for orders under £50). Delivery is £6 and with 20% VAT on top of all that I will end up paying £19.?? for 1.5m tube.

Damned expensive in the end!!

Their metric 3mm ID by 4mm OD is just under £2 per meter and their 3mm ID by 5 (or is it 6)mm OD is just under £4 per meter. They had some offcuts of those available as well...

So no small quantities and delivery is extortionate, but if you buy in bulk you *might* be able to resell the excess.