Pantograph Milling Coach Panelling For G3

[Bigjohn]

Using a mill to machine plastic and styrene I get very poor edge results………what’s the magic required please????

 

[JimG]

Using a mill to machine plastic and styrene I get very poor edge results………what’s the magic required please????

Use carbide cutting tools. I got this advice many years ago and I have successfully CNC milled panelled coach sides with excellent finishes on edges and surfaces. Here's my thread for my 1:32 scale coaches.

1/32 - Coaches for the Garden

One of these days I could have an operating layout in the garden and I'll need some coaches. For me, building coaches is a lengthy process so I thought I might make a start now so that there was a possible chance that something might be ready in time. :) I actually made a start last year...

www.westernthunder.co.uk

If you use HSS or carbon steel tooling, the heat generated during cutting causes the styrene to melt and deform, giving a poor finish. With the carbide tools, little heat is generated when cutting, probably because the carbide tools are much sharper, and the finish is excellent.

But I did find that I had to watch the speed of the cut. If your speed of cut gets too high, the styrene almost forms a bow wave in front of the cutter and your actual depth of cut deepens. So you can start to get grooves the width of the cutter on what should be flat surfaces.

Jim.

 

[Jon Nazareth]

Use carbide cutting tools. I got this advice many years ago and I have successfully CNC milled panelled coach sides with excellent finishes on edges and surfaces. Here's my thread for my 1:32 scale coaches.

1/32 - Coaches for the Garden

One of these days I could have an operating layout in the garden and I'll need some coaches. For me, building coaches is a lengthy process so I thought I might make a start now so that there was a possible chance that something might be ready in time. :) I actually made a start last year...

www.westernthunder.co.uk

If you use HSS or carbon steel tooling, the heat generated during cutting causes the styrene to melt and deform, giving a poor finish. With the carbide tools, little heat is generated when cutting, probably because the carbide tools are much sharper, and the finish is excellent.

But I did find that I had to watch the speed of the cut. If your speed of cut gets too high, the styrene almost forms a bow wave in front of the cutter and your actual depth of cut deepens. So you can start to get grooves the width of the cutter on what should be flat surfaces.

Jim.

That’s very interesting, Jim. I’ve machined styrene quite a bit when making rolling stock. With too big a cut, I’ve found that the styrene melts and sticks to the tool. I tend to make light cuts now. I’ve never used tipped tools before and may just give it a go.

Jon

 

[JimG]

That’s very interesting, Jim. I’ve machined styrene quite a bit when making rolling stock. With too big a cut, I’ve found that the styrene melts and sticks to the tool. I tend to make light cuts now. I’ve never used tipped tools before and may just give it a go.

I don't use tipped tools, they are small diameter carbide slotting cutters. My selection which does most of my work are 0.5mm, 1mm, 2mm and 5mm diameters with a small selection of ball end mills. I get mine from Drill Service, from this section of their web site :-

SDC - Carbide Slot Drill

Huge Range of Drill Bits & Accessories. Same Day Despatch before 4pm! Customs Available -Milling Cutters, Reamers & Much More | Order Now - 01293 774 911

www.drill-service.co.uk

I get the ones with the "Y" suffix which are the cheapest, but they work very well for me.

Watch out when using them since they are quite brittle and can chip or break at what seems the slightest provocation. In my early days of CNC machining, I dropped a very expensive, small diameter ball end mill from the collet chuck when taking it out and the end broke off when it hit the mill table. I have now developed the habit of wrapping my pinkie round the cutter when slackening the ER collet nut.

Jim.