RC CAR PART (Serpent Impulse and 705 chassises)

[gcamlibel]

I cut both Serpent Impulse and 705 chassises with Optimum BF 20 vario mill (and my cnc conversion of course)

Is there any one else who cuts aluminum RC parts?

[CNCadmin]

Very nice!

[gcamlibel]

Thank you,

Here is an other picture of the chasis

The chasis at left side which is unmounted is my product.

As you can see I reinforced front of the chasis by making the hole smaller.

[Cold Fusion]

Very nice. I'm in the RC car business and it's great to see other people enjoying the sport. Can you tell me the feeds for the aluminum as well as the thickness?

[gcamlibel]

I am racing at Turkey for 4 or 5 years as hobby. But I am very new at CNC and machining.

I wanted to use 7075 T6 alloy 3mm thick (0.118 inch) however it is not possible to find that material in my country (Turkey). Here at a local shop I found 5086 H32 sheets with 3mm thicness I used this material.

As I said before I am very new to machining. Therefore I find feed rate and spindle rpm with trial and error method According to me better voice and better surface give the best feed rate

I cut these parts with 3200 rpm spindle speed and 40mm per minute feed speed 3 fluet 5 mm diameter endmill.

Can you please give me advices about these data?

And finally an other picture

[gcamlibel]

To Cold Fusion:

What do you mean by "I'm in the RC car business"
Do you produce some spares or sell some parts or kits?

[Cold Fusion]

www.coldfusionracing.com

That is my business. We are about to come out with our very own electric buggy. Over 30 different pieces need to be machined for each car. Most of these will be in aluminum so I'm trying to get as much information as I can about how to cut it.

[3t3d]

Originally posted by gcamlibel


As I said before I am very new to machining. Therefore I find feed rate and spindle rpm with trial and error method According to me better voice and better surface give the best feed rate

I cut these parts with 3200 rpm spindle speed and 40mm per minute feed speed 3 fluet 5 mm diameter endmill.

Can you please give me advices about these data?

And finally an other picture [/B]

That is a chip load per tooth of about .004 mm per tooth. You must be seeing pure dust instead of chips. I usually start with a chip load per tooth of about Diameter/120. In other words for a 5 mm end mill, I might try to load the end mill with a chip load of .04mm per tooth per revolution. If you machine can handle it. <IF> you had the spindle, you could try to go as fast as 40,000 rpm. That woud allow you to go as fast as 2900 mm / minute.
The machine might not keep up at that rate however....

Bottom line, the numbers I use is:
chip load = diameter/120.
If you had the machine, I would try to go almost ten times faster for feed rate. you might be running out of machine to try that. With a large VMC, cutting that at 7400 mm/minute would be a breeze.
You are probobly limited by the rigidity of the machine you have. Try faster feedrate, and see if any chatter is due to the frame of the machine, or if it can keep up with a smooth cut. See if you can get more rpm. As much as you can get.

I seem to be rambling...
If you are going to make a business of it, you might consider prototyping on the small mill, and outsourcing orders of tens or hundreds parts to a larger machine. The speed and therfore the cost per part might make it worthwhile.

Hope this helps.
Pete

[gcamlibel]

Thank you for suggestions. My spindle is limited to 3200rpm.

I calculated s1000rpm and f113.8mm/minute from your data.
I will check that feed rate today. I will post the result.

There is no coolant system at my mini mill. When I spray WD40 cutting caracteristics changes. I cut s3200rpm f40mm/min without any coolant and WD40. At other trials sometimes aluminum melt or stick to tool.

[3t3d]

I was tired, and thinking about larger machines, with high pressure coolant. Without coolant, and a rigid machine, it is a whole new ball game. I woud definately use as much spindle rpm as possible. Heat buildup will start to weld aluminum to the cutter.

Pete

[ESjaavik]

Hi Gunol,

Nice to see that you got your machine converted an running in such a short time. Good work!
How about some pictures of the conversion?

You should try to get (or make) a mill chuck that places the cutter much closer to the spindle. I think the least rigid part in your setup is the long and slender chuck. It looks like a drill chuck?

You don't have a lathe? Yes you have! Tilt your head over on your shoulder and look at the mill. Doesn't it look very much like a lathe without a tailstock?
Get a 2MT blank (unhardened). Put it in the spindle and plunge it down onto a drill or mill bit held on the table. Ream to size. Make a hole in this holder for a screw to keep the bit from turning. Then you have a short, rigid and cheap holder.