The topic of heat treatment is one part science and often it seems, two parts smoke and one part black magic.
If the definition of heat treating that you have is close to the definition of steel that my neighbor has: “It’s dirty, it’s heavy, a magnet sticks to it and its made in fire,” then maybe you too could use an assist in figuring out how to communicate successfully with your heat treater.
We were pleased to see an article entitled ” How to Best Communicate Your Needs to the Heat Treater” co- written by PMPA Technical Member Nevada Heat Treating Vice President Patrick McKenna.
It was feature article in the April 2010 print edition of Industrial Heating magazine.
I predict that you will add it to your file of ‘articles you can use’ for sensemaking in this ever more complicated technical world that we harness for our customers.
You can read it at the link above.
Or contact Patrick at Nevada Heat Treating or Miles Free at PMPA and we’ll email you the article as a .pdf.
It will really be worth your time before you send that next batch of parts out to take a ride through the Fire…
Month: June 2010
The American Trucking Associations’ advance seasonally adjusted (SA) For-Hire Truck Tonnage Index increased for the sixth time in the last seven months, gaining another 0.9 percent in April. This followed a 0.4 percent increase in March.
The latest improvement put the SA index at 110.2 (2000=100), which is the highest level since September 2008.
Over the last seven months, the tonnage index grew a total of 6.5 percent.
We add this indicator to a growing list of indicators that show that this recovery has “legs” and we are now in what we have been calling “a new normal.”
Compared with April 2009, SA tonnage surged 9.4 percent, which was the fifth consecutive year-over-year gain and the largest increase since January 2005.
Year-to-date, tonnage is up 6 percent compared with the same period in 2009.
ATA Chief Economist Bob Costello said that the latest tonnage reading fits with a sustained economic recovery. “Truck tonnage volumes continue to improve at a solid, yet sustainable, rate. Tonnage is being boosted by robust manufacturing output and stronger retail sales.” (emphasis ours!)
Bottom Line: Trucking serves as a barometer of the U.S. economy, representing 68 percent of tonnage carried by all modes of domestic freight transportation, including manufactured and retail goods. The latest ATA numbers confirm our manufacturing markets continue their recovery.
The American Trucking Associations is the largest national trade association for the trucking industry.
Read the full article here.
And lets hope that precision manufacturing keeps on truckin’..
What do you think? Have your shipments increased as reflected in the ATA report?
R. Crumb Keep On Truckin sticker
What’s it gonna be? Feed or Speed?
For a given production rate of metal removal, better tool life is obtained by using heavy feed and low speed.
Sorry, Flash.
Less horsepower per cubic inch of metal removal is required for heavier feeds (see the diagonal lines on the chart below.)
This also means fewer revolutions of the work (or tool) to get the job done.
This reduces wear on the tool.
Slower speeds results in less friction, less heat.
Surface finish declines as feed rate increases, but it is usually acceptable until a critical rate is reached (see the numbers along the curves above- they are the values for surface finish in RMS).
In steels, grades that are rephosphorized and renitrogenized can take heavier feeds than steels that are not. (That’s why I’m showing C1213 at 0.07-0.012 phosphorous compared to C1215 at 0.04-0.09 Phos.)
Here is another graph to illustrate the effect of feed rate and surface finish.
As feed rate increases bottom (horizontal) axis so does surface roughness (vertical) axis measured in RMS.
The contract shop industry remains seduced by the siren song of speed to reduce cycle time.
Perhaps the proper use of the feed approach can make you some new friends among your customers…
These data are based on HSS tools. Obviously using carbide one needs to have sufficient speed to take advantage of the carbide.
Bottom Line: Increased feed rather than speed can result in longer tool life and less problems than increasing speed and dealing with the heat that results.
What is your approach? Speed for cycle time? Or feed for minimizing HP for removal and longer tool life and fewer problems?
Feed or speed? What’s it gonna be?
Photo credits:
The Flash: http://www.ramasscreen.com/wp-content/uploads/2009/07/Flash-Adam-Strange-Aquaman.JPG
The Incredible Hulk: http://keneller.typepad.com/photos/uncategorized/2008/06/14/lou_ferrigno_as_incredible_hulk.jpg
Playstations’ genius image of Finger of the Hulk beckoning link: http://www.sparehed.com/wp-content/uploads/2007/03/ad-hulk-playstation-2-2006.jpg
The Precision Machined Products Association is proud to serve its member companies in the precision machining industry.
We know the value that is added by our industry to our everyday lives: Ground and Aerospace Transportation, Safety, Appliances, Food Packaging, Tools, Off Road Equipment, Medical Devices- all of these markets rely on products made by precision machining shops to make their technologies work.
We are excited to provide information, resources, and networking opportunities that advance and sustain our members.
The precision machining industry is known to the statisticians in Washington, D.C. as NAICS 332721: Precision Machining.
Precision machining is defined this way: “This U.S. industry comprises establishments known as precision turned manufacturers primarily engaged in machining precision products of all materials on a job or order basis. Generally precision turned product jobs are large-volume using machines such as automatic screw machines, rotary transfer machines, computer numerically controlled (CNC) lathes or turning centers.”
The last year for which the U.S. Census shows data for our industry is 2006. That year, there were 2,528 firms and 2,582 establishments. The figures tell us that there are few multi-site precision machining companies in the United States.
Our industry employed about 76,640 men and women to make highly engineered, precision products in 2006. Our products typically are components of some other device (like a car, airplane, satellite, appliance or cell phone). They are not finished products that you would expect to buy at a store. Our parts are the technologies that make the other technologies work. That’s because we can produce to high precision and in the needed quantities.
What is the bottom line for this industry? The latest data for Value of Product Shipments of NAICS 332721 is for 2005. The precision machining industry created $9,791,795,000 of product shipments that year.
That’s $9.8 billion of sales.
For more info, read our article in Production Machining Magazine here.
Great question came in the other day.
“Since the computers control the machines, why do we need to have physics in our graduation curriculum?”
I won’t tell you the State Board of Education that was looking at removing Physics from the high school curriculum.
Apparently they don’t see a need for a person entering the Precision Machining workplace to know any physics.
If they don’t understand the forces around them, how can they keep from getting hurt?
Here’s what I shared with them.
Since everything is computer controlled– that’s the new MAGIC, right?- why would any high school graduate going into the workplace these days need to know any physics? I’m guessing that, “so they can understand how the electricity that powers his machine the computer, and the lights,” isn’t a good enough answer.
1)Power and Work: All machines are horsepower rated. This determines what jobs they can perform. Materials are machined based on horsepower per cubic inch of removal per minute. By the State Board’s reasoning, “Since the clock takes care of the minutes, are we okay to just not know any of this?”
2) Mechanics: This is our craft! We need leverage, thread pitch, gear ratios, belts and pulleys. We calculate the surface feet per minute of rotating tools or workpieces, given the RPM and diameter. Even the computer needs this info. Cams, clutches, springs, motors, friction and frictional losses- these are physics. Bearings, force, stress, strain- these are applicable to understanding the machining task regardless of machine control type. Compressed air- expansion, horsepower required, volume, fluid flow…
3) Heat: Heat is the enemy in machining operations. Why not learn a little bit about this? Savvy shops today are using infrared thermography to detect bearing wear in equipment. Some kinds of tool failure are caused by heat. Understanding insulation, conduction, thermal expansion and contraction are key if the parts will be in spec after they have cooled down post machining.
4) Sound: Decibel measurement is important as applied to occupational exposure. Harmonics come into play on tools and workpieces as oscillation- chatter. Water hammer in plumbed systems and fluid power applications.
5) Light and optics: Non-contact gaging using lasers, optical projectors for quality control; optical flats for high precision measurements rely on counting interference bands… We use portable spectrometers for product sorting. Someone in the shop will need to have an understanding of spectrums, wavelengths, and emissions if they are to be more than an idiot operated go/no go gage.
6) Magnetism: Magnetism can cause surface finish problems if chips cling to work. There are several types of magnetic tests performed in our shops and those of our suppliers. They use eddy currents, permeability, gauss, oersteds, saturation, coercivity. We employ magnetism for proximity detection of parts, magnetic workholding , and for testing. It goes with out saying that it is magnetism in the electric motors that drives our machines.
What do you think about this topic? Do the people showing up looking for work have what it takes to understand your process? Or are they merely able to do what they are told?