[fomaz]

Hello.

I need to produce several tools like the one in attachment (and other formats), normally all from carbide blanks.

What is the best way to produce this, so that the tool would be as perfect as possible? Or by your experience how would you grind it (machine, type of grinding disc, method...). A brief description, or any sugestion would be high appreciated.

I am willing to invest on a new process on my company.

For testing proposes, I have grinded it a green stone and then I finished with a diamond grinding disc on a manual tool grinding machine. The tool cuts, but I belive that there is a better method to produce this, especially because of low duration of the green grinding wheel and the heat produced.

Thank you

[cad01]

outsource to Micro100. They will be consistant and frees up your time to do something else. What are you using these for? maybe there are stock tools already offered?

[fomaz]

We machine plastics with them (the cutting tool is for rubber).
There are not standard inserts and there are no supplier for them.

If I was in USA, I had no doubt in outsourcing. We are in Europe and until now I could not find a single supplier for all the tools that I need and I asked for many company's. Buying in USA make the tool expensive because of import taxes and so on, so I was hoping for a solution in house.

Any idea on the working method? Use only diamond, diamond and silicon carbide wheels, a mixture of both?

[fomaz]

Some advice from experienced tool makers ?
None?

[acme-stribel]

I would first try some off the shelf supplier such as Sandvik as we use their tooling. The 2 off items you pictured are of simple design so their manufacture is no real problem with conventional grinding equipment. One suggestion that i would advise is the holder for aligning these for both the grinding and when setting up for machining would be to use the Sanvik method which has the rear end (opposite of cutting end) at approx 30 degree
angle to always have correct tool tip cutting on centre line.

As regards grinding wheels for this. Use a Diamond wheel of approx D126 for doing the roughing and leave approx 0.03 to 0.05mm for finishing per side or approx 0.06 to 0.010 on diameters. Then using D300 to D400 grit for finishing the tool profile. Attention to keeping the diamond wheel clean using
fine dressing stick (gently feeding it into wheel by hand to open its struture) will avoid and undue heat in finishing if coolant is not being used.

[fomaz]

Thanks "acme-stribel"

This was the answer I was expecting. Clean and usefull.

Just one thing: Brands of grinding wheels is important? Recomendations? And the stick that you talk about, it is a white stick ?

Thanks again

[acme-stribel]

Firstly in regards to getting the best possible result in relation to making tools from Carbide Rod or blanks, naturally the type of carbide selection is important as a low cost std carbide as in some lathe tooling ( carbide brazed to steel shank and priced £4 to £8 in supply catalogs ) is adequate for general use. For more industrial production a Micro- Grain carbide is required as this will hold a sharper cutting edge without chipping but is more difficult to work with and requires a good grinding set-up.
Basically 1 A Truing device for making the diamond wheel run concentric on its holder in relation to m/c spindle. ( when trued do not remove from holder, but can be removed from m/c spindle and for very very fine finishing a quick truing each time wheel holder is fixed to spindle for best finish) After Truing the wheel a Dressing Stick is used (fed in by hand, if have coolant on is good) to open the the face of the wheel (remove debris from truing) and the wheel is ready for use. The wheel on this brake dresser is usually 60 grit
for truing 80 to 120 grit diamond wheels and for finer 100 grit for 320 and finer grit diamond wheels.

2 Selection of Diamond is generally for roughing D126 (not sure of grit size) and for finishing D76 or finer D46. The D46 (350 to 400 grit) is
ok and to go for very very finer 600 to 1200 grit require vert specialised use as basically it is so close to a honing process and any undue use will cause
heat build up and edge cracking. The Concentration C50..C75..C100..C125 of a diamond wheel is generally that a C100 gives good wheel life in regards to its cost. A Diamond wheel of C50 is relative less expensive and will need more dressing and truing (wheel surface wearing, not keeping flat) A C125 is best but also the most expensive. In relation to Bond type a Resin bond is okay for wet and dry grinding.

3 Stability of machine and condition of spindle (generally if an excellent perfect grinding finish (free from vibration ripples) can be obtained from grinding a hardened steel with 100 grit well dressed Aluminium Oxide Wheel then this the starting point to doing good CARBIDE GRINDING on this machine.

4 As the cost of Truing attachment (if purchasing new ie Norton
Brake Truing Attachment) is high and the Diamond wheels depending on source and also the limitations as regards doing some work such as radius grinding with is limited to usually revolving the work piece as forming any profiles onto diamond wheels is not easy and also cost effective as the depth of diamond is usually from 2mm to 6mm in depth on to wheel material(aluminium os steel) A Norbide Stick 12x5 by 80mm long can be use to do outside radius on wheel by hand etc for general use.

For more information the Norton Abrasives for the Industrial Market site is very informative in relation to the use and maintenance of Diamond and also CBN (for HSS and Steels). Their Industrial Catalogue page 187 on is for all its Diamond products. This is a good source of information and as I use some Norton items,there are alot of sources of these product's. Because of some wheel and holder spec it is not possible to find is a catalogue and I mainly have these manufactured in UK. As I use mainly Swiss grinding m/c's a very good supply is easily obtained there for consumables.

When doing the pricing of carbide tooling alot can depend on blank material price ie. Dia 12mm is approx £50 to £55 per 300mm length (Micro-grain) Dia 6mm approx £20 per 300mm length.
So in keeping with all these items there is a need to consider to buy in or manufacture in house. At the moment alot of tooling specialist and grinding shops are looking for more business and is a customer is willing to do prompt payment alot of reductions from their normal pricing can be got.
I regards some of my purchasing with suppliers I have had had good dealings (fast delivery times as quoted,no mistakes in order quantites) I prefer to pay in advance to get a very very favourable discount as they have no credit factoring to allow when calculating a quote as is in 30..60..90 day credit accounts. I DO NOT RECOMMEND this only to past people whom you have had good dealings with.
Hope some of this info is of help.

[DK7]

Hi fomaz,
Just an info for you, tools like the drawings will cost about 100 Euro maybe a bit more for the bigger one. Buying carbide rods, grinding wheels and spending time grinding it, could be more expensive? Also, did your company ever tried DLC (Diamond Like Coating) especialy for plastic?

[Ballix]

Great advise, Thanks!

[TheBigJW]

We wire edm these for customers. Works great.

John