What questions to ask a producer when baying a carbide for tools 1

[Viktor]

I am about to buy carbide to make cutting tools or carbide inserts for a particular job. There are a number of carbide suppliers. How to select a good one and what questions to ask to compare the quality of carbides from different suppliers? Given: Each supplier (producer) maintains that his carbide is the best in the market place.

Viktor

http://viktorastakhov.tripod.com

 

[rakes]

First thing you ask is the grain size. Micro-grain carbide tools retain their edge better under adverse conditions. Transverse rupture strength (for solid carbide tools) is another parameter.
But the best way is to get a sample and cut it on your material. Nothing like seeing it with your own eyes.
If you can give more details of your job, may be I can help.
regards
rakes
esrakesh@rediffmail.com

 

[Viktor]

Dear Rakes

Thank you for your answer. However, it leads to other questions: (1) smaller grain size is not always better (chipping) so how to correlate the gain size with a particular job? (2) TRS is a nice characteristic but of no use in metal cutting because it has no correlations with cutting parameters (see the standard method for its determination).

As you pointed out – get a piece of the carbide and try. Although it looks very attractive and direct, a logical question arises: which one of multiple types of carbides available from any producer? The second question is even more interesting: what cutting regime, cutting geometry, etc. to use in this test? Would you expect the same result on a new CNC of high stiffness and on a 20-year old screw machine? What parameters in this test I have to measure – an average shop does not have a dynamometer or even simple toolmaker’s microscope (to measure wear)? Please do not suggest to talk to sails reps – no use.

I would appreciate your opinion.
Viktor

http://viktorastakhov.tripod.com

 

[Curmudgeon]

Viktor
Almost certainly better than talking to the sales reps - - try talking to the fellows in your shop. Find out who they listen to about machining, tools, etc. It may be that one quiet fellow working off to the side. It might be a vendor/rep that they've come to trust over several years. It might even be their old shop-teacher from high-school.
Whoever.
Sit down and have coffee with that person. Pick their brain. Describe the situation you're looking at. Get their advice. Then use that advice as a starting point with your negotiations with sales reps.
Machinery's Handbook will give you some good, practical information, though perhaps not in the detail you may need for this situation.

In a worst case - buy from a reputable supplier. They won't sell you 'junk' (or they won't stay in business for long). While their product is being used, test samples from the two or three (no more) other vendors you are interested in.

If your shop lacks the tools to do a proper test (as it sounds), you might wish to contact a local college or university with an engineering program - - the professors may welcome the variety of working with your 'real-world' application(s). Even some of the 'tech-schools' with machining courses may have the testing capabilities - - and certainly should have knowledgeable instructors. Be prepared to pay for a service such as this.

2 cents of advice from:

Curmudgeon

 

[Viktor]

Dear Curmudgeon

Although you propose one of the possible ways, it is still a way toooo subjective. According to the proposed way, my decision should be based on opinions. Well…We are in engineering and thus prefer to operate with objective parameters. I used to teach: in God we trust, anybody else should bring the data. So far, nobody tells me what are these data should be for the selection of the proper grade of carbide for a particular job and how to chose a carbide producer. I am in contact with some of carbide producers and to my great surprise they do not have reliable cutting data for their products. Their research laboratories are doing ‘strange’ cutting tests and their measuring facilities are rather out-of-date.

Regards
Viktor

http://viktorastakhov.tripod.com

 

Viktor,
Most all mfgs. of incerts have product literature to
help with proper tool selection. Aquire as many as you
can and make an informed decision. Try a few & if you
feel that they don't do the job you can try a different
grade/brand before spending a fortune. Not knowing the material or machining process of your job makes it impossible to suggest a mfg. I use different brand & type carbide tools for different jobs & so do all of the other
machinists I know. Different machinists will use a different tool to do the same operation depending upon
their methods. This goes for engineers, process designers/ analyzers, & cnc programers too. There is no "best" carbide out there. I can cut iconel with HSS tools if the conditions are right, ie. speed, feed, tool radius, rake, clearance coolant/lubricant etc. In the cnc world you probably have only machine operators, I hope you have real machinists in your shop, they will possess knowledge of metallurgy, casting, hardening & tempering etc... and have experience with most machining operations. Go out into the shop and get your hands dirty & get a basic "feel" for machining. Observe and ask questions, maybe even run a MANUAL machine with a piece of scrap so you can experiment. The only stupid question is the one that doesn't get asked. Then when you ask a machinist (not a machine operator) to use a tool or proceedure he won't tell you where to put it. You will both have respect for each other and can open a productive dialog, you will expand your knowledge base and
make yourself more valuable.

 

[Viktor]

Dear Automach
I really appreciate the time you’ve spent trying to help me. You’ve made a number of good points and suggest a way to deal with the problem. However, I could not accept this way because it is still tooooooo subjective. I have been working in metalcutting industry for the last 30 years and started as a machinist (manual machines – turning, milling, drilling, grinding, etc.). Therefore, I believe I have all this feeling of cutting you’ve mentioned. Unfortunately it does not help much in the educated selection of carbides.
You’ve written ”Most all mfgs. of incerts have product literature to help with proper tool selection. Aquire as many as you can and make an informed decision” – knowing state of the art in the carbide industry, I can assure you that the product literature is of small help in making my decision. The information provided is too general and sales reps fail to answer even simplest questions about their products (for example, what is the radius of the cutting edge of your inserts; what is the thermal conductivity of your carbide; what is the effective inclination angle of your inserts, etc.). You’ve written “Try a few & if you feel that they don't do the job you can try a different grade/brand before spending a fortune.” It seems to be direct way to check carbide inserts. However, a number of questions arise. First – try implies I should compare these inserts. What is the criterion (criteria) for such a comparison? Tool wear (too expensive test), cutting force (need to have a dyno), etc. What regime to use for the comparison? The same for all inserts – I do not think so because each of these may have own optimum cutting regime. What coolant/lubricant and its flow rate (temperature, purity, way of supply) to use – the same for all inserts?
You wrote: “I hope you have real machinists in your shop, they will possess knowledge of metallurgy, casting, hardening & tempering etc... and have experience with most machining operations”. Yes, I do. But…how to correlate this knowledge with particular characteristics in carbide insert selection? If I tell you that I have a steel, give you a dialed description of its metallurgical state (composition, hardness, grain size, size and distribution of inclusions, grain boundary energy, defectiveness of lattice, etc) could you correlate these parameters with the corresponding parameters of a carbide?

Let me make is simple. When you wont to buy a car, you will consider a number of its technical characteristics: horse power and torque, fuel consumption, acceleration rate, standard and optional features, type of wheels, reliability and crash (front and side impact) characteristics (at least reliability rating in the Consumer Digest), relative price and many other. All this helps you to make an educated choice. Now, image if you go to buy a car and a dialer tells you – buy a few different and try them. What would br your reaction?

Why you cannot use the same approach in carbide selection? The answer is rather simple – carbide producers won’t let you. You simply do not have relevant characteristics for carbides because you never ask the suppliers about these characteristics. Unfortunately, there is no a consumer digest for the carbide industry so we, end users, are in dark only because we do not ask proper questions.

Regards
Viktor

http://viktorastakhov.tripod.com

 

[sbc]

viktor, I like your analogy about car shopping.
When buying cars or tools I like to consider
reliability & how long it's been in production.
A model with 5yrs. production will have a track
record, & parts (ie. brakes,exaust sys.) should
be available & reasonable in the future.
Tools of new design sometimes don't stay around
very long because for some reason they don't
become popular. I see tool holders thrown out
because they didn't perform, or the inserts aren't
popular/economical/available. The rapid changes
and variations in insert design, along with the
lack of tech. info. makes it look as if the mfgs.
want us to experiment & buy lots of product. I
found Sandvik claiming support, service & training
on this site, mmsonline.com. There is contact info,
mfg links & also a forum that might be helpfull.
You may also find info at

http://www.cncmagazine.com.,

http://www.indexable.com/ict020/ivt020.html,

http://www.anconline.com/troubleshooting.html,

This next site lists carbide mfg links, copy &
paste to your browser

http://dmoz.org/Business/Industries...ng/Tooling,_Tools,_Consumables/Tools/Carbide/

I did a search on "carbide insert selection" at
google.com to find these links. I didn't have time to
go through any in detail, and there were over 3,000
results. Somewhere in there could be some answers.
It's good to see that you came up through the ranks,
I deal with too many book born engineers, nuff said.
Hope this helps!!

 

[Viktor]

Dear SBC
Thank you very much for your time and the help. I will post a detailed opinion about the Sandvik selection after Christmas. I may consider adding some comments on the manner used by the Third Wave in the comparison of different carbide using their simulation software.
I wish you and all participant Merry Christmas and Prosperous New Year hoping we continue our productive discussion.
Sincerely, Viktor

 

[Viktor]

Dear SBCThis is the beginning of my analysis of the list of carbide and carbide too manufactures you’ve suggested. Let start in the alphabetic order:


A.B. Tool, Inc.

http://www.abtoolsinc.com/

Lets take the first tool from the list
Carbide Tipped Keyseat Cutters.
Suggested cutting data:
Ferrous: 150-250 SFM 0.001-0.003 IPT
Non-Ferrous: 1K-3K SFM 0.002-0.006 IPM

As seen, the ranges are so broad that definitely they cover everything. All materials are divided into Ferrous and Non-Ferrous – Is it nice or what? Could you compare “a non-ferrous high titanium ally and “a ferrous gray cast iron”? Which one is better in terms of machinability?

FAQ: Estimated comparison of CIM per HP for various materials, (using carbide):
Cold Rolled Steel (1018) 1 CIM per HP
Aluminum, Magnesium, Plastic, Graphite 4 to 6 CIM per HP
Cast Iron, 303 0.7-0.8 CIM per HP
Tool Steel, Alloy steel 304-316, 17-4PH, 6AL-4V 0.4-0.6 CIM per HP
Inconel and other High Temperature Alloys 0.2-0.4 CIM per HP
Is it nice that cast iron and stainless steel are in the same group in terms of the power required for cutting? Tool steel and stainlesses (304-316) are the same. Is delirium or nightmare or what? And people still buy something from these guys – I rest my case.

Advanced Carbide Tool Company

http://www.advancedcarbide.com/

On the title page: “In addition to the standard line of carbide burs, Advanced Carbide Tool Company manufacture's special carbide burs used in power generation and the manufacture of power generation equipment and aircraft engines.” I should confess – I did not have any idea that a deburing tool (simply called a bur) can be used “in power generation.” Is it used as a special fuel or they learned how to utilize the heat energy generated in cutting?
If you try to find any clue on the cutting regime or tool material, you are wasting your time simply because it do not exist on the webpage.

Advanced Carbide Tooling info@advancedcarbidetooling.co.uk
The webpage does not contain any specific info on the carbide used for the cutting tool as well as on the recommended cutting regimes. I am wondering what is the objective to have such a website.

Advanced Cutting Tools

http://advancedcuttingtools.net/

No any info about carbide or cutting regime.


American National Carbide

http://www.anconline.com/

After looking at the webpage of this company one should wander what exactly this company is producing not even mention about carbide type or cutting regimes.

Baxter Carbide

http://www.4carbide.com/

No carbide grade is provided. The recommended regime are shown below:

General Feeds and Speeds (surface feet per minute)

Turning / Facing / Boring Grooving / Parting
Grade Material Finishing .004-.010IPR General Purpose .008-.025IPR Roughing Over .020IPR Most Applications .004-.010IPR
BC2 Non-ferrous metals Austanitic stainless Super alloys/Refactory metals 600-1500 300-500 ----- 400-1000 250-400 70-120 400-600 180-270 50-90 300-900 180-300 70-120
C5C CNC Free machining steels/Martensitic stainless steel 400-750 350-600 300-450 300-700



I do not think that it can be use even to the first approximation not mentioned a comparison with other carbides or geometries.


Carbide Concepts,

http://www.carbideconcepts.com/

Only one link mentioned carbide at all: Engineered Carbide
What it says:
As a supplier to the Aircraft, Automotive, Petroleum, and other major industries, our strict attention to details are well documented.
We provide standard and special form carbide i.e. grooving, cam-ground disposable, all types of threading tools, multi-tooth thread chasers and specific tooling for Bearing manufacturers.
Our vast resources can provide tools in Premium High Speed Steel, Carbide, Cermets, Ceramics, Silicon Nitride, and Diamond.
In addition to providing a diverse range of high quality cutting tools, we can also provide in-house technical engineering to assist the customer in the development of Special Application Tools.
Please contact us for your Non Standard Tooling.
As you see, plenty information for proper selection and comparison.
Carbide Specialties, Inc.

http://www.carbidespecialties.com/

The most valuable info on the webpage is a link to a game: The Lands of Sorren. Nothing else is useful.
Carbide Technologies Inc
The company provide, at least, some properties of their grades in

http://www.carbidetechnologies.com/Grades.htm.

Unfortunately, this info has a number of flaws: (1) the characteristics provided do not have any correlation with cutting properties. For example, TRS, specific gravity (it is a new parameter introduced in physics by this company instead of specific weight or density) and hardness have a little to do with wear resistance at different cutting conditions and with maximum cutting parameters which can be used ; (2) the grain size variation is toooo wide, (3) there is no grades which may cover ISO P class known as the most suitable for machining of steels and alloys.

 

[sbc]

viktor, Sorry to send you on a wild goose chase.
Like I said, I didn't have time to investigate
any links in detail. I don't know where to find
the information you seek. I machine a variety of
materials from plastics to iconel cladding. I
select my tooling based upon my experience,(I
know, 'Too Subjective'). If you do find all of
this info and crunch all of the numbers, what
have you got? A cemented c-6 tool works great
for facing a 6" mild steel flange, What happens
if that flange has a bolt circle drilled through
it? Are there 5 pcs. to machine or 500? Now, is
it most economical to go & buy tooling for this
job, or to slow the speed & use what you have?
If facing a shaft to the center, is your lathe
capable of variable feed & speed in order to
maintain sfpm & chip load? If a part gets work
hardned (by a poor machinist), How do you select
a tool without sending the part to a lab? Many
applications require different geometries for
1 operation, ie. when turning a shaft excessive
cutting pressure will cause deflection, & a tool
with minimal cutting pressure will not handle
a large cut. There are endless senarios. How do
you find the perfect grade of carbide which also
has the optimal geometry? Many times you cannot.
I agree that most info on the subject is useless,
probably due to the fact that tool selection for
machining is 99.9% application specific. Just
because a Kennametal incert fails where a Carboloy
insert of the same grade & geometry works, doesn't
mean that one brand is better than the other. It
only shows that there are differances between
the various manufacturers. Most of the formulas
for the properties of various materials were reverse
engineered. 'Let's add more carbon & see how the
properties change, then produce a formula which
gives the same results as the tests'. Then test
it again and presto! we have a formula. I have
setup, (from the ground up) and now run a machine
& fabrication shop designed to support the science
departments at Connecticut College. As such I often
find myself acting as a liaison between theroy &
practicality. I applaud your efforts.
I don't like to discourage anyone
in their quest for knowlege. Perhaps you could try
to contact someone who teaches the trade as curmudgeon
suggested. Again not to discourage or insult you
but, no matter how much info you aquire, I
don't think your great-grandchildren will live
long enough to see a black & white answer to carbide
tool selection. There are just too many variables.

 

[tomwalz]

As near as we can tell there are about 5,000 grades from about 1500 suppliers.

"C" grades are worse than useless. see:

http://www.carbideprocessors.com/Brazing/book/05.htm

I have a couple hundred pages on this web site on brazed tools, coolants and related matters. That doesn't begin to cover the subject.

Find a salesperson who uses numbers and try his stuff.
Set a standard for performance and test from there.

At the levels of production and tolerances in modern machine shops almost anything can make a difference. See my article on Fine filtering in Cutting Tool Engineering for an example.

 

[092455]

Victor:

Carbide is nothing more than a "recipe". Alot like generic medicines. However, many carbide producers use "reclaim" in their manufacturing operations. They reclaim their previous lot run, when machine in soft state and re-use in their "next run" close to this particular grade.

Take a look at "The Book of HardMetals" by Kenneth J. Brooks. It lists all the carbide manufacturers and their "Grades" (at least the ones who want to be known)

Again, 95% Tungsten & 6% cobalt (C2) is strictly that, no matter who "makes" it.

 

[Viktor]

092455

First of all, 95+6=101.

Second, the chemical composition of carbide says nothing. There are many more important parameters and properties that define the quality of carbide. As a result, two carbide having the same comical composition but produced by different companies (for example HB and PlanseeTizit) show at least two-ford difference under the same working conditions. I can explain why exactly it happens.

Regards


Viktor

http://viktorastakhov.tripod.com