Advice on quoting and working with n35 tungston carbide?

fettersp · Aug 4, 2020

I got a quote for a 3x2x .5 inch pieece of carbide that has a .50 hole in the middle with an 82 degree c sink with a .03 chamber on all sides. Iv never worked with carbide before but I imagine it would have to be ether ground or edm? My surface grinder only has aluminum oxide and cbn wheels.
The tolerance for every thin id 2 grand except the hole that's 10 grand.
I do have a ram edm.

Can you get precession size stock for carbide?
How much would you price a job like this?
Is it even worth doing if I have limited knowledge of working on carbide?

CarbideBob · Aug 4, 2020

n35? don't know this.
Normally you would buy the blank from Quality or others with the hole preformed in it at the green state and then grind the top and bottom and periphery to size dependent on tolerances.
At .002 all around you are going to need to be able to grind carbide. At one off this not a cheap piece of raw stock.

Milland · Aug 4, 2020

Is it really tungsten carbide, or one of the many tungsten "Heavy Metal" mixes like tungsten-nickel? I've cut a few varieties of heavy metal (tungsten nickel iron, tungsten copper iron) for electrodes and the like.

Heavy metals generally cut fairly well with regular carbide tooling, if what you have is truly carbide you need to get more info from your customer as to composition and manufacturer. You can EDM carbide, but it's slow. You can use CBN, but it's slow and damages the wheel.

You'd want diamond grit tooling for machining, and that can have a learning curve that gets expensive.

Tungsten Alloys: W + Ni, Fe, Cu, or Mo

fettersp · Aug 4, 2020

Sorry that was my bad. The print says the material is tungsten carbide ND25 not n35. Im not sure if this is a grade or not? I cant find anything about it.
what exactly is the green state and I didn't know they formed the hole/ 82 degree c' sink in it already? They want a total of 15 of these. I don't know if I should do this or not as the material price seems like it would be enormous?

Milland · Aug 4, 2020

If it's green that means it's an oversized "compact", with a binder to hold it together. It'll be fragile, and if sintering/final treatment shrinks it significantly you may need compensation of the cut dimensions so the final part meets print.

So good news - easy to cut. Bad news - fragile, and prone to chipping.

I've never cut green carbide, but have cut green aluminum oxide preforms. Sharp tools, careful fixturing (don't crush it), and patience...

What is Tungsten Carbide or Hard Metal?

CarbideBob · Aug 4, 2020

ND25 also not a grade I know, people invent grade numbers like water.
Dad's favorite was to add 69 so VC-2 would go on a print as CES-71.
Green state is before the carbide is sintered. At this point the carbide is like chalk so you can drill and form it easily.
Hence the name preforms. You do not work green carbide, this is done by your supplier.
15 is a decent size run on such a part but you will need to be able to grind it to size as it will come to you with about .020 stock on all sides.
The hole you will not touch so this is a top and bottom, grind 4 sides job. One could wire the sides or OD but that painfully slow.
At the min you will need diamond wheels for your surface grinder and lots of water or oil flowing.
If you want to pursue it I'd contact Quality or HB and ask for a quote on a preform to your print. They may know this grade number and have an equal.

To give you an thought I'd get a preform, T&B on the Blanchard with 4 flips as the stock will not be flat (1/2 hour of work plus setup for the 15), Hit each side on the SG with a face wheel (30-60 seconds max per side plus setups), clean, pack, ship.
Order processing and quotes on both sides, pack, ship and setups would swamp the actual shop run costs.
Raw stock price will be the big one and I have no idea where that price tag comes in. 3 by 2 by 1/2 is way above stock material plus you need a hole and chamfers.
Ram EDM not a great idea.

Get a price on molded material and go from there. Both sources above good and well respected guys. Don't scrap one.
Bob

fettersp · Aug 4, 2020

CarbideBob said:
ND25 also not a grade I know, people invent grade numbers like water.
Dad's favorite was to add 69 so VC-2 would go on a print as CES-71.
Green state is before the carbide is sintered. At this point the carbide is like chalk so you can drill and form it easily.
Hence the name preforms. You do not work green carbide, this is done by your supplier.
15 is a decent size run on such a part but you will need to be able to grind it to size as it will come to you with about .020 stock on all sides.
The hole you will not touch so this is a top and bottom, grind 4 sides job. One could wire the sides or OD but that painfully slow.
At the min you will need diamond wheels for your surface grinder and lots of water or oil flowing.
If you want to pursue it I'd contact Quality or HB and ask for a quote on a preform to your print. They may know this grade number and have an equal.

To give you an thought I'd get a preform, T&B on the Blanchard with 4 flips as the stock will not be flat (1/2 hour of work plus setup for the 15), Hit each side on the SG with a face wheel (30-60 seconds max per side plus setups), clean, pack, ship.
Order processing and quotes on both sides, pack, ship and setups would swamp the actual shop run costs.
Raw stock price will be the big one and I have no idea where that price tag comes in. 3 by 2 by 1/2 is way above stock material plus you need a hole and chamfers.
Ram EDM not a great idea.

Get a price on molded material and go from there. Both sources above good and well respected guys. Don't scrap one.
Bob

Ok that doesnt seem nearly as bad as I thought. But I may have some stupid questions.
1. What do you mean by the 15 run on?
2. What is t&b om yhe blanchard?
3. Why would I od grind the sides? Wouldnt using a sine bar on the SG work fpr yhe sides?

CarbideBob · Aug 4, 2020

fettersp said:
.......
2. What is t&b om yhe blanchard?

Why do I feel like I'm being baited?

fettersp · Aug 4, 2020

Your not I hoesnlt do not know what that means

CarbideBob · Aug 4, 2020

No idea the who why what or how here but I will do you the courtesy of a friendly goodbye.
Bob

triumph406 · Aug 4, 2020

fettersp said:
Ok that doesnt seem nearly as bad as I thought. But I may have some stupid questions.
1. What do you mean by the 15 run on?
2. What is t&b om yhe blanchard?
3. Why would I od grind the sides? Wouldnt using a sine bar on the SG work fpr yhe sides?

It's probably best you don't quote the job, risky parts, especially when you evidently don't know what your doing.

DDoug · Aug 5, 2020

Here's a place that does "large blocks"
Leech Carbide Home Page

On the west side of Pa, where in O-HI-O are you located ?

bigbee67 · Aug 14, 2020

fettersp said:
Sorry that was my bad. The print says the material is tungsten carbide ND25 not n35. Im not sure if this is a grade or not? I cant find anything about it.
what exactly is the green state and I didn't know they formed the hole/ 82 degree c' sink in it already? They want a total of 15 of these. I don't know if I should do this or not as the material price seems like it would be enormous?

I recognized ND-25 as an old Firth Sterling>Teledyne>Stellram>Kennametal rough core die nib grade. I am a walking repository of useless and obsolete grade and insert information.

I found it in an old catalog:
70%WC/30%Co/5%Tac+NbC+TiC
HRC 83.0
Density 12.95g/cc
TRS 250ksi

Ken1965 · Jan 19, 2023

You can also try Carbide Technologies Inc. in Fraser Mi. They do custom preforms and I believe that they can hard grind also. They have done some nice work for us over the past few years.
WWW.carbidetechnologies.com

DDoug · Jan 19, 2023

Ken1965 said:
You can also try Carbide Technologies Inc. in Fraser Mi. They do custom preforms and I believe that they can hard grind also. They have done some nice work for us over the past few years.
WWW.carbidetechnologies.com

Do you work there ?

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