[manakawari]

so i posted a thread a couple weeks ago asking for help finding a material that machines easily and with fine detail(small lettering) but can also stand up to higher than normal heat ( about 250 degrees would work.

My cnc machine is a roland mdx40a and while it can mill softer metals like aluminum, it does so very slowly and because i need such fine detail, i cant imagine using something like a 1/64 inch cutter on aluminum and not breaking the bit the second it touches the material.

My mill is great for plastics and the job i am looking to do is mill embossing dies for deep leather embossing.

The way it works is the dies (normally metal) are pressed in a heat press for about 30 seconds to leave the deep leather impression.

I milled a couple from 1/2 inch acrylic and they came out fantastic and left a nice embossing but the problem is that the heat begins to melt and warp them after only 2 or w pressings, they also begin to crack as well.

I have been searching for a non metal alternative so that i can more easily create these on my mill but im literally at a loss for a suitable material.

PEEK plastic and similar high performance plastics have been suggested but for a .5" 12" x 12 " piece, the cost is over $1000 dollars!!!!!...thats insane for just a sq foot on a material.

I also looked into machinable ceramics..the specs suggest this material would work well but those are even more expensive!!!!...im looking for something in the .5" thick at a price about $100 - 200 per sq foot or cheaper.....does nothing at all exist?? aside from the high cost of peek, it seems like overkill, i do not need something that can survive 4 or 500 degrees, 250 degrees would be enough..in fact acrylic seems pretty close because the dies work for one or two pressings, they just slowly begin to warp after that.

I looked into teflon but i believe the cost per sq foot for that is about 500 dollars, again, cheaper but still too expensive....i just cant believe that something hard, easy to machine, and something that can stand up to 250 degrees without melting doesnt exist for less than $500 dollars a .5 inch foot.

Please help me im desperate!!!!

[george4657]

Try Delrin (Acetal)
Check this link for cut offs on Ebay
CNC, white items in acetal store on eBay!

Delrin is nice to machine but it may be too soft.
I have not tried in in high temperatures but it works as zero backlash nut on a cnc machine

[SocalPE]

Don't know if this will help. Oh, and forgive me if the pic doesn't show up... I don't know what I'm doing

Attachment 332478

[mcphill]

You could try Corian. Get scraps for cheap from a countertop manufacturer local to you or off eBay.

[LeeWay]

Brass or bronze also machine very easily. Higher cost for the blank, but would last far longer than any most plastic. Delrin may be a good choice, but I don't think it does detail very well unless you have a very good machine.

Also some of the reason you cannot find subjects like this through the search function is because not everyone labels the thread correctly.

[manakawari]

thanks guys, this is a huge help..metals arnt an option because like I said, my cnc machine is too slow with metals (roland mdx40a) and besides, I need very tiny letters and small details...I cant imagine the small tools I require surviving metal cutting.

Based on the chart provided, it look like ppsu (raydel) is what I need, next I find out the cost...fingers crossed

[SocalPE]

.5x12x12 of PVDF stock runs around $150, I believe that is the cheapest on the list.

[LeeWay]

Have you ever tried cutting brass. It doesn't machine like other metals. Maybe more like a soft cast iron. It machines easily with no coolant and can hold details well. Honestly I would try that first before spending that kind of money on an unknown plastic. It may be so hard that you could not machine it either.

[elfrench]

, i cant imagine using something like a 1/64 inch cutter on aluminum and not breaking the bit the second it touches the material.

1/64 inch cutters are positively huge. With the proper feeds and speeds you should have no problem cutting aluminum with even smaller endmills.

[LeeWay]

Right. The smaller the tool, the smaller machine requirements up to a point. They should still be very rigid, but can have low strength and horsepower needs. High speed spindles aren't even required and may actually be too fast.

Most plastics have other machining issues as well. Very few plastics cut or machine well with anything less than just the right recipe.

[dharmic]

FWIW I've used a cheap chinese router to quite successfully "engrave" a 3mm deep metal stamp in annealed carbon steel using a 0.1mm (0.004") nosed 10º V engraving cutter without snapping a single piece. Use a feed and speed calculator to work everything out including depth per pass, add a little leeway to the results. Went surprisingly well and the results came out very clean (2mm high text which is clearly readable in the stamped piece). Then harden and temper the punch when you're done.

[underthetire]

+1 on brass, easy to machine and will hold heat in better than plastics (I assume you want to heat it). I engrave it all the time on our New Hermes engraver at work, not a very rigid machine/spindle.

Sent from my A3-A20FHD using Tapatalk

[manakawari]

Thanks again guys, really great stuff here and I appreciate all the advice..as much as I would love to create these embossing dies with metal, I just don't think my mill is up to the task...again, I'm using a Roland mdx40a and while I have had some success with brass and aluminum in the past, I just feel that with this mill, and with this need, it's just too slow to be a realistic solution....if I were to use this mill to create one of the bigger and deeper engraved dies that I need. Aluminum or brass would literally take me all day to mill one while the same die in acrylic takes an hour or less....the need presents itself quite often for me to produce a half a dozen different embossing dies in a single day and when you consider the difference in machining time, we are talking about the difference of a week or a few hours...our factory does product development and sampling for the fashion industry and rarely do we do any sort of production so while a metal die is obviously ideal, it's overkill in this situation because my dies are typically used for creating a dozen samples at best...acrylic will get me 3 or 4 samples before the die starts warping or cracking so I really feel I'm pretty close to filling my need with a plastic, I just need a higher performance one to get me my 6 to 12 pressings..I will buy some samples of the materials suggested and see where it gets me...what about Teflon?? Does that machine small lettering well?? Is that not an option?...just out of curiosity, what bit do u guys suggest for doing very tiny lettering in brass or aluminum?? I have tried in the past to mill in aluminum using the aluminium presets in the Roland software with a 1/64" round end mill and it snapped almost immediately...I just can't imagine a bit like this surviving....I have some of the pointed end conical bit's but I generally use those for engraving and not for true 3d milling because the deeper the engraving goes the wider the bit becomes and as a result fine detail becomes impossible....lastly, what generally is considered the softest or easiest metal to mill??....I hear of some embossing die makers using magnesium as an alternative for a cheaper die when mass production is not needed...makes me assume magnesium can be milled much faster and easier so perhaps that's the solution...another material I have been wondering about is carbon or graphite....this can definitely survive the heat, most likely the pressing and is very cheap...I just don't know if it can be machined to any realistic degree of fine detail...anyone have any idea? Perhaps carbon is my solution and not a high end plastic?

[LeeWay]

Its called free machining brass for a reason. Aluminum has grades that machine well and others that are pretty gummy and can only be machined with specific recipes that most smaller machines cannot handle. It is easy to get your hands on some that will not play fair.
The gummy stuff can break bits instantly. Now a ball end mill is not really designed to be a plunge cutter either. It is designed to cut from the center out and upward. They can be used for some shallow plunging with the right settings, but not on a material that gives you a hard time anyway. Ball end mills work best as rest cutters. They come in behind after a regular end mill has cleared out most of the material. For speed sometimes you can just use a bull nose cutter if the finish isn't critical. I don't think that would work for you.

Now about your machine. I am not sure why you say it is too slow for metal. some metals require slow speed and some do not.
While there are plenty of soft metals around, that isn't a property to focus on. The softest metal might be lead and zinc, but certainly not suitable for pressing and not much heat either.
I haven't tried carbon or graphite, but I know carbon fiber is not that easy to machine, but can be done.
Good luck with it. Post some results when you can.

[manakawari]

thanks for the response , when i say "too slow" i mean the work flow where i am requires me to produce samples very quickly and its just faster to machine acrylic than metal on my machine...i can produce 10 plastic dies in the time it takes to machine a single one from metal...considering these dies are typically only used a handful of times, its just better for me to use an easier and faster material to machine.

My machine sucks for metal, trust me.

[LeeWay]

Yeah.
It looks like it is geared more toward PCB's. In fact, phenolic might be a good choice to machine.