Re - coating, a "must" after sharpening!

[Konrad]

I'm running the CNC Mill and I sure love those coated carbide cutters.

A brand new 1/2", 4 fluted top Quality Kennametal, I can run 2days of milling, verses 2 hours of a sharpened one!

Well....been telling my Boss [He does tool grinding] to look into a coating set up!
But for a small Business, it's Impossible! very expensive proposition!

Is there a small setup out there, lets say, 50 - 100 endmill a week?

What do the small Grinding shops in general do??

Konrad

[HuFlungDung]

Personally, if I'm not running the cutter all that deep, only a relatively small amount of the flute near the end gets worn. So I figure why spoil all that flute that hasn't even tasted iron yet?

Regrinding the flute also erodes the rake angle created between the inside face of the flute relative to the land. The closer you get to the cutter axis, the less positive the flute becomes.

The gullet gets shallower and has more difficulty with expelling the chip in softer materials.

So, to preserve the coating and get an extra life or two out of the cutter, I simply cut it off at the wear depth with a narrow diamond wheel. Then, back off the ends of the teeth a little and then its back to the mill.

[Konrad]

Thanks HuFlungDung,

You are such a busy guy on this forum and a great Inspiration to others, special thanks!
Are you actually getting any machining done yourself, or you have good help?

I should have mentioned, 90% of the time we do the same thing, just re do the ends!
My front edges just don't stand up anymore!

Konrad

[HuFlungDung]

Konrad,

Yes I do get some machining done. Some of it is not too adventuresome, you know, rerunning old programs for the umpteenth time It is nice when something new comes along.

[Mouldmaker]

We also use Kennametal cutters and drills on our machining centre. When they are worn out, we send them back to Kennametal for resharpening and recoating at approximately 1/4 the price of a new tool.

[Konrad]

That sounds reasonable!

Something came in mind, lets say, you recoat a endmill 3 times, are you not getting too much coating
on the tool, where the coating never has touched the Iron?

What's the ideal max # of times, for recoating?

Are most Tool Grinding Shops not getting them recoated????
Toolgrinders, please talk!

Konrad

[sdigeso]

If all your doing is wearing the end of the tool, why don't you look at an inserted tool, wear the inserts only cost you about $12 and you can use them on both ends. I am looking in this at the shop I am in. We only use the end of a 3/4 rougher and then trash them. I will be testing insterted tools hopefully be the end of April.

Just my thoughts.

Scott

[Konrad]

Thanks for your reply Scott,

I'm using also 3/4" dia. 2 flute, inserted tool.

I'm not aware of any smaller cutters, like I have mentioned, 1/2", with inserts.
You just can't substitute a solid "Sharp" [4 flute] carbide tool, with anything else!
When you go this small, the cutting geometry is suffering, when inserts are used.

Konrad

[Mouldmaker]

Konrad,

When recoating a tool, the previous coating hat to be taken off and the cutter is then coated again.

Scott,

We use cutters with inserts when they are above 16mm (0.6 inch), but for a 1 mm (0.039 inch) (or even smaller) cutter you have to use solid carbide cutters.

[Jake]

Hello Konrad !!!

If your working with toolgrinding and wants satisfied customers
you must be able to regrind and recote a tool so that its as good as a new tool or even better.

this means regrinding a standard endmill includes , grinding of flute ( with compensation of the core diameter in relation of the stock removal on the OD) , grinding of the OD 1 & 2 nd clearance,
gashing the end , grinding of the end teeth .

all this operations with the same geometrics as the endmill had when it was new , to read all geometrics you need some kind of a measuring machine , there are vision systems , optical , and manual ones .

now when the tool is regrinded we can recote the tool , ofcourse with the same coating as the original one.

to answer your question about the possibility to recote the tools
there is to my knowledge no cheap coating systems that will pay off with the amount of endmills you wrote , its not very practical either since its realy a lot of steps to put a PVD layer on a tool.
(inspection , off coating , washing , recoating , mm )

why not send the tools to a company that does coating, normaly you will have the tools back in 48 hours.

sorry for writing a novel but since there were other questions i put in the hole package.

best regards // Jake

[Konrad]

Thanks Mouldmaker & Jake,

Yes Jake, it looks like we have to send them out, I have Kennametal to give me a quote.

Since, we just started to grind endmills on a Walter 5 axis CNC machine, there is not a problem anymore to grind the cutters as new, all we need now is the coating on carbide.

How is it with your Carbide Endmills, are they mostly worn on the very end, like from our Customers, or you have to sharpen everything? If you do, then the standard diameter is gone, and that's for some CNC Machinenist, like myself a problem, you have to redo the programs.

Can you recoat the tools yourself, or you have to send them out??
Oh...I just seen your posts on Walter CNC grinders, it looks like you sharpen the tools for the woodindustrie,
Are some of the tools also coated??
Here, I have not seen it yet.

Why your # of Posts still stands on # 5, after you have posted so many times??

Konrad

[CHAD]

QUOTE "How is it with your Carbide Endmills, are they mostly worn on the very end, like from our Customers, or you have to sharpen everything? If you do, then the standard diameter is gone, and that's for some CNC Machinenist, like myself a problem, you have to redo the programs."\

THAT SHOULD NOT BE A PROBLEM AT ALL IF YOU ARE USING CUTTER COMPENSATION, G41\G42 YOU USE THE OFFSET TO COMPENSATE FOR THE TOOL DIAMETER>>>>>>