[Al4350]

Hi all,
I’m about to do a heap of reasech and development on race car parts out of alloy.
What tooling is best for shimmy finishes. Theses parts will need to be spot-on. Majority of parts will be programmed with master cam.
Thanks
Allan

[awerby]

What are "shimmy finishes"? Is that an Australian term? In general, HSS tools can be sharper and cheaper. Solid carbide is stiffer, and less likely to "shimmy" when cutting. They are better for harder, more abrasive materials and hold their edges longer. Various coatings are applied to them which can help their performance with particular alloys.

[Al4350]

My bad, was supposed to be shinny, mirror like finish.
Should we be using coated hss tools? Or just plane hss tools?
I’ve mostly worked with high tensile steel. So hss,
Was never an option.
Cheers
Al

[CNC_Sh]

Better use solid carbide mills, only uncoated with polished edges.

[Ydna]

For steel workpieces you'll see a very noticeable surface finish quality increase with carbide tooling (not to mention the machining time will be quicker too). Naturally it depends on the specifics, but you can achieve EXTREMELY smooth floor-finish surfaces with the proper carbide parameters.

[Al4350]

For steel workpieces you'll see a very noticeable surface finish quality increase with carbide tooling (not to mention the machining time will be quicker too). Naturally it depends on the specifics, but you can achieve EXTREMELY smooth floor-finish surfaces with the proper carbide parameters.

Thanks for reply, I know about using carbide for Steel.
I’m machining billet alloy, I need a good finish almost mirror.
Wondering what tooling to use. I’ve gotton different advice from
Local tooling suppliers.

[triumph406]

Thanks for reply, I know about using carbide for Steel.
I’m machining billet alloy, I need a good finish almost mirror.
Wondering what tooling to use. I’ve gotton different advice from
Local tooling suppliers.

Try some YG Alu-Power 3 flute endmills. Likely you'll get the results your looking for.

[LeeWay]

You did not mention which aluminum alloy or grade. Each different class and series is formulated for certain characteristics.
Some even in the same series machine totally different from each other. For instance 6061, which is likely the most common type for machining is not difficult to machine and you get good results easily. 6063 on the other hand is gummy and likes to throw burrs. It too can be machined, but you have to really develop the right cutting recipe for and use extremely sharp tools. Once the tool gets a little worn. it is history. It would not be a candidate for shinny finishes.
As for mirror finishes, I doubt you will see that straight off the machine. It would likely need to be polished afterward.

[Machineit]

With steel it is sometimes more dependent of the steel for the finish. Many steels with cut nice, but tear. Meaning that the metal removed will bring little chunks of the finish metal with the chip. For great finishes the ones like 4140 prehard have a really nice finish. Over all, the HHS can get a better finish to start, but will dull sooner and machine slower. Probably best to go with carbide.

What you program with makes no difference at all. Hard to tell you more without more info.

[RCaffin]

Hey guys - what is the point of giving suggestions for steel when the OP wants to machine ALLOY? (Which I assume means aluminium alloy given that he is talking about race car parts.) Waste of electrons.

I suggest using good aluminium-specific HSS cutters with air blast and misting - MQL. Without the air blast you will get recuts which will ding the surface. 2-flute or 4-flute - a good Q. I suggest 2-flute as the larger gap lets the air blast get rid of the chips better.

But if you want SHINY I think you will still have to polish. Felt disks and rouge.

Cheers
Roger

[CL_MotoTech]

Good gravy, what a mess this thread is.

Assuming your race car will use 6061-t6, which is the most common alloy for race car parts (at least the ones I make), flute count and chip evacuation and cooling will be your first concern. 2 and 3 flute will be your best bet, they have more space for chips to be removed, that means you get a better finish. I use a lot of 3/8" and 1/2" end mills, I face almost exclusively with a 2" 4 insert (round) face mill. Good high pressure coolant is needed. HSS, carbide, and coated inserts/mills produce great finishes given the right feeds and speeds. Carbide and coated end mills tend to cut a bit faster.

Like Lee and Roger mentioned, a true mirror like finish is going to be tough without some polishing.

[Machineit]

Here aluminum is generally not referred to as ALLOY.

[LeeWay]

Here everything is an alloy.

[CL_MotoTech]

It's Aluminum Alloy. North Americans shorten it to Aluminum, Australians shorten it to Alloy. They are both referring to the same thing. Pure aluminum has rather poor mechanical properties, as a result it is assumed that shortened "alloy" and "aluminum" monikers both refer to Aluminum Alloy.

[Machineit]

For a great finish it is hard to beat the Alu-Power endmills. Super nice finish. They are center cutting too, but I would not do a whole lot of plunging without some side movement, as they tend to load up. But, for finish, they are great. The are also very reasonably priced on eBay.

https://www.ebay.com/itm/5-Pcs-1-2-Y...72.m2749.l2649

Mike

[Heavymetalcnc]

I will second the Alu-power end mills. They work great, at a great price.
You will be looking for high helix high positive cutting edge with only 2-3 flutes.
They polish the carbide to keep the material from sticking to the end mill. This is, I think, the key to a good finish.

[RCaffin]

Agree - it's the polished or honed finish on the cutter which helps a lot.

Cheers
Roger

[coolwater]

OP never confirmed that Alloy meant aluminum, but if thats the case a 3 flute with a ZRN coating is definitely the way to go. Good chip evac and the coating will give extra life to the carbide by increasing the lubricity against the aluminum. Something like this would be a monster in your ALLOY ; )

https://titancuttingtools.com/order/...em?itn=TC65932