Foam XL hot wire cutter

[Robin Hewitt]

Doesn't everyone?

http://www.robinhewitt.net/Falkirk.wmv

[Boyan Silyavski]

Any idea for possible cheap solutions for the long rails ??? I decided on 1200 and 2200mm travel .

I am currently exploring options for the way to do it and its seems it is hit and miss

-The oozenest C beam seems perfect but they stock it up to 1500mm. And i need 2500mm

-Mjunit is ready made system but such lengths from China will be 1500euro in total to receive it here after customs

-Similar problem with Motedis, too long travel. I will wrtite them now but i see the 6mm steel bearing rod that fits

-meanwhile talking with Fred from BST

-The german CNc Discount does not answer me or i would have bought the rails from him


Any idea how to achieve that travel on the cheap? And best with stuff from Europe? And if not on the cheap, just on the reasonable side? I will not buy Chinese rails with Hiwin Price tag from EU. Now if they are cheaper ...

I am starting to think people don't want to take my money

[charlieuk]

I have been trying to come up with basically exactly the same thing for myself to cut eps block to put on my cnc to cut my surfboard however I need to be able to cut down 16' x 4' x 2' blocks.

I have been thinking about it for a year or so trying to figure a way to get some cheap linear motion. I was wondering about just using a wheel that runs on the ali extrusion but then thought maybe that would not be enough. then there are some of the methods available on cnc router parts but in the end I always come back to just trying to find some cheap low quality square rails as they will probably be better than all the above and a lot easier to set up.

my plan for the drive was a belt, it should be more than accurate enough

looks like your going for just two axis rather than 4? I would love 4 axis but think I will probably go 2 for simplicity.

[charlieuk]

the one in this vid uses booth belt and wheels straight on the extrusion giving something cheap and simple.

http://www.youtube.com/watch?v=-kWGnj5FeI8

[Boyan Silyavski]

the one in this vid uses booth belt and wheels straight on the extrusion giving something cheap and simple.

http://www.youtube.com/watch?v=-kWGnj5FeI8

Thanks for link, but i don't like bulky things


Deadly accurate, dependable, simple. Price starts from 16.900$

Thats exactly the machine type and design i hate. Big servos, where nema 17 will do the job, 10 times bigger than needed aluminum profile. In other words, overbuild thats showing absolute lack of understanding. Not me.

I have been trying to come up with basically exactly the same thing for myself to cut eps block to put on my cnc to cut my surfboard however I need to be able to cut down 16' x 4' x 2' blocks.

I have been thinking about it for a year or so trying to figure a way to get some cheap linear motion. I was wondering about just using a wheel that runs on the ali extrusion but then thought maybe that would not be enough. then there are some of the methods available on cnc router parts but in the end I always come back to just trying to find some cheap low quality square rails as they will probably be better than all the above and a lot easier to set up.

my plan for the drive was a belt, it should be more than accurate enough

looks like your going for just two axis rather than 4? I would love 4 axis but think I will probably go 2 for simplicity.

Mine will be 5 axis in fact. But it will be used as 2 axis most of the time as what i will be cutting is letters mostly. Plus i dont have the place to fix it properly for now. So it will start as 40cm wide 2 axis, that could be transformed to 2m wide 4 axis for under an hour, when need arises and when i find bigger place.

To sum it up for the linear movement and structure:

1. Motedis failed me this time. Blah Blah Blah, we dont cut and ship anything larger than 1980cm. Though it says on their web if one needs such thing to contact them to arrange. Now the funny thing is that i found DOLD Mechatronik in germany, that is their partner and does that, plus he has 3m screws and is willing to ship them to me. WTF. I am in the process of buying the profile from him.

2. I prefer the leadscrew TR10x2 for now, simply put - it will be more reliable and cheaper. Screw is 20 euro per 3m . Double row angular bearing pack is 2 euro from china. All else will be printed or machined from plate of aluminum. It could be made also with the Gt2 steel belt , it will be same money but will take me more time to design it, as i don't like much long double belts.


3. I have changed all structure from 3060 to 2040 slot6 , as it will be good enough for the job. I know, not typical for me to not overbuild, but it's not needed here. Final length will be 1300x2600mm travel will be around 1200x2400, as i remembered that locally i have 600x2400 foam sheets

-The original Hiwin for 6x1300 and 6 carriages / yes i will be but connecting them/ is around 800$ and after all will be around 800 euros. Quite expensive

-The Chinese MGN12 6x1300 and 6 carriages will be 300$ and say 60 euros import tax. Probably they will do the job, if something does not move right, will open it and change the balls, as i have seen people on Youtube do. So thats the winner

-The Mjunit is around 1500euro after taxes . is very nice looking but at the end of the day is just aluminum profile with steel rods and U bearings. But again i will say it looks very professional.

-The C beam from Oozenest Looked nice but is only 1500mm so again has to be attached together. Will cost me as much as do all from Chinese MGN12, so better not deal with rollers/ if they are not angular contact?/

-I lost patiance trying to explain Chinese that i need it for a slow foam cutter, otherwise there are some that could make me the whole linear movement cheap from 1204 ball screw , alu profile and square rail. Shipping would be then 300$ for that lenghts .


4. Now some interesting stuff. Long ago where there was no 3d printing and i had crappy belt driven machine, i have tried to make something with delrin ball that could slide on top of Bosch profile. Nowadays its even easier. Couple that with 2040 profile and we have a winner. 500 balls are 20$, each carriage has around 18 balls i believe. So i could use them for even something else. I will buy the balls even if i go with Hiwin

No plans here, but i have figured it out with 8mm balls:




Another one, looks nice and have downloaded the files. Waiting for him to see if he will pass me Step file, no just STL:



Check how they compare:




With the preload feature i dont see a reason why it will not work perfectly for a foam cutter especially where they will not even make a noise., Not to speak of that i could print them in POM. I will wait a day though as i have another idea inspired from i don't remember which bearing block.as i simply like them less bulkier.

There was a bearing that looks like hiwin block and inside it has 4 big spheres that enter the rail channel in a very similar way as abobe. But inside the block there is arrangment of very small bearing spheres that the big sphere lay on. So basically no recirculation as the above but a kind of. The only benefit will be to lessen the bulk and make them look more professional.

[charlieuk]

i wasn't talking about the motors or the price just the simple drive system, and if it does the job then ....

I cant see the point in the printed carriages they will never last under any sort of load and ether the plastic will fail or the surface of the aluminium will deteriorate. I would rather just use something like a cheap set of skateboard bearings and make a arrangement that runs down the groves of the aluminum that way at least the have a larger contact area and the aluminum should not deteriorate

8 x 4 eps blocks are not light but if your frame is not supporting the foam and on a solid floor you can probably get away with a smaller frame I wouldn't even consider anything lighter than 40x40. you need a relatively high tension in the wire to reduce sag and drag if you want straight lines and want any sort of reasonable speed without to much curf. and if you are ever going to do 4 or 5 axis you will need stiffness in the frame to get that, unless you build a complex frame that will likely cost as much.

[Boyan Silyavski]

any idea of the force needed to tighten the wire for radiation cutting? i think its less than 1 kg in mass, if weight is used. i cut now using 0.16mm wire and a small spring, for sure less than 1kg pull.


I see the benefit of the big aluminum profile and 20 size rail, as that was my initial design, using 3060 profile. But that's more for industrial use where somebody will work for you and will not take care of the machine. Doing it for myself, i think 2040 is enough. Still have not bought either yet. And have a day or 2 to think it over. Price wise will be just a bit more expensive.


By the way cages could be printed from Delrin, so they will be ok for the job. I have read reports on a printer after 1500h was perfectly fine

[charlieuk]

any idea of the force needed to tighten the wire for radiation cutting? i think its less than 1 kg in mass, if weight is used. i cut now using 0.16mm wire and a small spring, for sure less than 1kg pull.


I see the benefit of the big aluminum profile and 20 size rail, as that was my initial design, using 3060 profile. But that's more for industrial use where somebody will work for you and will not take care of the machine. Doing it for myself, i think 2040 is enough. Still have not bought either yet. And have a day or 2 to think it over. Price wise will be just a bit more expensive.


By the way cages could be printed from Delrin, so they will be ok for the job. I have read reports on a printer after 1500h was perfectly fine

I'll see if I can figure it out, it's more than you think as with a manual one you are normally pressing down on to templates which tenshions it further. The larger the block your cutting the more tension you need or the slower you have to go. It's a combanation of having the right temperature, the right tenshion and the right cutting speed so as to get a clean cut and not too much burn back

At a guess I would say mine is probably 2-3kg tension but I'm cutting relatively slow and and not too hot.

The cost saving is minimal on the Ali, I know what I would do..

I see less of a problem with the printed cages than I do with the balls them self. If using steel ball on Ali you don't need to be a materials scientist to know which will be the winner!

[charlieuk]

If I can't find some linniar rail at the right price I will probably go for a aragement like this but with a deralin caridge that houses the bearing but allso as a guide even though the bearings are almost a perfect fit width wise. I will find it hard to find the cost saving of linniar rail viable over the time it will take to design build and set up my own method