[klaymonster]

I want to manufacture plastic cast molds on a CNC machine. The products will be designed in CAD and milled into molds which i could put together and fill with the plastic resin. Thats the idea anyway but thats about as far as I have got. I need to know if its concievable that a milled peice could have a surface smooth enough to then mould say a clear lens for a taillight. Maybe with some minor buffing or sanding? If i had a 18"x18"x6" approximate working area is there a machine that jumps out as an ideal for this scenario? is it under $5000 i hope? Thanks a lot guys. First post btw I look foward to getting to know a lot of you.

[hoss2006]

Welcome Klaymonster!
18"x18"x6" for mold work under $5000? Sorry, not much hope there.
For that capacity you'd be looking at a VMC like a Haas and a used one
at that price would no doubt need thousands for refurbishing.

[SCzEngrgGroup]

I want to manufacture plastic cast molds on a CNC machine. The products will be designed in CAD and milled into molds which i could put together and fill with the plastic resin. Thats the idea anyway but thats about as far as I have got. I need to know if its concievable that a milled peice could have a surface smooth enough to then mould say a clear lens for a taillight. Maybe with some minor buffing or sanding? If i had a 18"x18"x6" approximate working area is there a machine that jumps out as an ideal for this scenario? is it under $5000 i hope? Thanks a lot guys. First post btw I look foward to getting to know a lot of you.

18" x 18" x 6" is HUGE! Even a Bridgeport can't do that. The small machines are typically limited to 4-8" in the Y axis, and 10-16" in X. Those are total travels, actual usable work envelope is almost always smaller. I have a large Bridgeport clone, which is 34" in X, 14" in Y, 16" total in Z (but much less usable Z travel for a given operation - quill travel is only 5"). You're talking VMC territory there, which == $$$$.

You don't generally get a "perfect" finish right off the machine. Molds are usually surface-finished after machining, to either polish, or apply a consistent texture. Polishing could be done manually, but is VERY time-consuming. To get to a surface that you *could* polish, and that would give good injection molding results, you'd need a VERY "tight", precise machine - one with truly *zero* backlash, and very high accuracy. That's not your typical hobby machine.

Regards,
Ray L.

[klaymonster]

I appretiate the frank responses. (...and speedy too!) You'll have to excuse if i get tears of broken dreams smeared in my response. *drip* *drip*

Well it looks like i've got quite a bit more reading to do, I imagine i'll be spending a lot more time with all of you. In the meantime does anyone know of a review/buyersguide type resource in this field?

[Andre' B]

I need to know if its concievable that a milled peice could have a surface smooth enough to then mould say a clear lens for a taillight. Maybe with some minor buffing or sanding?

You will be looking at machines in this class.
http://www.yasda.co.jp/la_English/

is it under $5000 i hope?

That will get you a few tool holders and maybe an end mill or two.
Add two more zeros on that and you will be all set.

[klaymonster]

Haha thanks again you guys. My naiveness has struck again... :withstupi

[brfgmike]

As said before, plastic molds must be polished to a mirror like finish, or it would reflect any imperfections. Even in small production line which i assume you thinking about it would take a lot of time to hand finish every single piece. However hand finish would not be as good as from a good mold. Anyway don't take me a wrong way, I do a lot of things the hard way myself before i learn to make it wright, which most of the time equals that my trying to save the money, costs me twice as much.. if you know what i mean. I do know some small manufacturer in Europe who specializes in plastic mold making. Economy is tough these days and if you have a part drawing i can put you in touch with them for a quote. I am not trying to advertise here or make money of you.
Just suggesting... Best regards Mike

[scudzuki]

And as a former moldmaker I can assure you there is no job more tedious and miserable than polishing, especially with an optical finish the goal.
Joe

[Harryman]

If it's short run stuff, you could always polish the plastic.......

[CROSSHATCH]

His best bet is for a Router. Perfect brand comes to mind, K2!

http://www.k2cnc.com/


-Jason