Cheap machine guard?

[JamesJames]

My homemade CNC machine is nearing completion. I'm looking for some protection against flying bits and pieces for myself – with a window so I can watch it working. Cost is a big factor.

I see commercial sites offering to build using mesh, sheet metal, and polycarbonate.
Not being very trade-savvy, I need help with descriptions of suitable economic materials.

I'm looking at a single wall that I could stand behind, perhaps 1 - 2 metres wide and 2 metres high (3 – 6 feet wide and 6 ft 6 ins high), with a viewing window.

Any suggestions?
TIA
Jim

[mxtras]

Acrylic or polycarbonate sheeting is the the first thing to come to mind.

If you attach a smaller piece of acrylic to a flexible arm then to a magnetic base, you could then simply position it in the path of the offensive, flying chips rather than having a relatively large sheet that you have to clean and store. Just a thought.

Oh - you do wear safety glasses, right?

Scott

[ConKbot of Doom]

I would avoid acrylic sheeting, cracks too easy... As for polycarbonate/lexan it definitely is tough, but large sheets can get expensive. if you want just a viewing port, I would get some black iron piping, some caster wheels, make a frame, and put some 1/2" plywood, sealed up with something to waterproof it if you're using coolant. and polycarbonate windows inlaid in that.

We use big polycarbonate gaurds on our 5 axis routers to keep any broken tools contained... though most the time the tools like to fall to the floor while spinning like a top and skitter across the floor anyway...

[InspirationTool]

Do NOT use acrylic or "Plexiglass" it isn't as impact resistant OR as easy to work with as polycarbonate or "Lexan".

You can get Lexan at Home Depot. If you can't afford that much, use plywood instead for the areas you aren't looking through.

-Jeff

[JamesJames]

Thanks all for your advice. As it's flying tools and such, rather than chips and bits, that I'm most afraid of, I'll go for the polycarbonate viewing panel in a plywood screen.

Thanks again.
Jim

[thkoutsidthebox]

Im buying my polycarbonate as cut-offs that they have. I'm going to have a look and pick some suitable ones out and was told they'll be a lot cheaper than buying a full sheet. See if your supplier has polycarbonate cut-offs that they'll sell you cheaper, then as suggested use it as windows.

[Geof]

When buying polycarbonate cut-offs be careful. Some polycarbonate used for glazing has an abrasion resistant coating so it does not scratch as easily as uncoated polycarbonate. This coating makes the polycarbonate much more brittle; not as brittle as acrylic but enough that it is possible to shatter it with a good hammer blow. Uncoated polycarbonate can withstand hammer blows.

[JamesJames]

Thanks.
So what thickness of uncoated polycarbonate are we talking about?

[Geof]

Originally Posted by JamesJames Thanks. So what thickness of uncoated polycarbonate are we talking about?

Our VMC's and lathes have 3/16" and 1/4" windows. I suppose I should translate 5 or 6 mm. They also have the warning sign that polycarbonate wondows and doors will not stop all projectiles. So remember it is not indestructible, just a good first protection.

[paulC]

Just wondering. CD's are polycarbonate I think. If you scrape off the backing you end up with a thin piece of clear polycarbonate. The backing comes off really easy once it starts to lift. If you then used several layers of this as a window would that catch a fast flying object. Sometimes layers stop things better than a solid and sometimes they don't. What do you think?
Paul

[thkoutsidthebox]

I think it'd cost more to buy enough cd's than to just buy the polycarbonate. An 8x4 foot sheet of 6mm costs me €120 incl VAT.

[paulC]

Originally Posted by thkoutsidthebox I think it'd cost more to buy enough cd's than to just buy the polycarbonate. An 8x4 foot sheet of 6mm costs me €120 incl VAT.

While that would be true of new CDs. I have hunderds of old software CD's available to me. Paul