As Director of Technology and Industry Research for PMPA, Miles brings 38 years of hands-on experience in areas of manufacturing, quality and steelmaking. He helps answer "HOW?","WITH WHAT?" and "REALLY?"
The team at PMPA member Keystone Threaded Products (Valley View, Ohio) shows us that “precision” doesn’t necessarily mean “tiny” as the company threads the ends of 20-foot long, 10-inch stainless steel bars for a metalworking press. The thread is 10 ¼ inch: 4 UNJ RH applied to each end of the 3 ½-ton bar.
20-feet long, two ends to thread, 3 1/2 tons of precision
At Keystone, the operators roll the thread form onto the material, which makes for a stronger thread. Alignment and following the process is critical to assure a good thread.
Thread rolls create the thread form on the workpiece.
Multiple passes are needed to build up the thread to the proper dimensions.
Half a million pounds of pressure are imparted on the rolls to plastically move the steel of the bar into the thread form. Read the gage.
Obviously, it takes knowledge, skills and experience to apply half a million pounds to produce precision work.
Rich says he has rolled larger bars, but skills, experience and a great team to work with create the can-do spirit that makes precision manufacturing a great career.
Here’s another look at a finished bar. Precision does not necessarily mean tiny.
While manufacturing growth remains essentially level, certain sectors served by the precision machining industry grew nicely in the year ending in April 2016. Dr. Chad Moutray, chief economist at National Association of Manufacturers, has compiled and shared the data for the past year in manufacturing.
Fabricated Metal is the sector in which precision machining is classified, and this data shows a minus 3-percent growth for the period of April 2015 to April 2016. But our shops also provide engineered components for Motor Vehicles and Parts (up 4.3 percent), Miscellaneous durable goods (up 5.2 percent) and Computer and Electronic Products (up 2.9 percent).
While the actual year-over-year growth for manufacturing eked out a 0.5-percent growth rate, there were clearly winning and losing sectors, as the chart below shows.
Here is a recap of the markets typically served by our precision machining shops: Machinery, Fabricated Metal, Aerospace and Miscellaneous Transportation Equipment, and Electrical Equipment and Appliances were down, while Miscellaneous Durable Goods, Motor Vehicles and Parts, Computer and Electronic Products showed gains ranging from 2.9 to 5.2 percent.
According to Dr. Moutray, manufacturing rebounded somewhat in April, as manufacturing production grew 0.3 percent, just offsetting the 0.3 percent decline in March. In April, renewed strength in the Machinery sector (up 2.4 percent) and Motor Vehicles and Parts sectors (up 1.3 percent) were positive signs.
The PMPA Business Trends Index of Sales for April 2016 declined from the year’s March high of 131 to April’s 122. That 122 reading is up one point from the 2015 calendar year average.
While the economic news is not bubbling with enthusiastic reports of growth, we think the fact that the industry is operating even or above last year’s average is a positive story. It beats the alternative.
Certain sectors served by the precision machining industry grew nicely in the
In our shops, order of magnitude reflects the relative scale of our processes and helps us see what is and is not applicable to the problem at hand.
If you have an intermittent or periodic problem, start counting frequency of occurrence, and then figure out what the order of magnitude is compared with your process.
To solve periodic or intermittent problems in our shops, the first step after identifying the problem is collecting data about when and how often it occurs. Then, comparing it with the orders of magnitude that occur naturally in your shop can help you narrow down the likely causes.
Relative frequency can be a big help when you figure out that the frequency has some relationship or equivalence to some aspect of your process. If the frequency is about equal to two occurrences per bar, then it becomes relevant to look at bar ends first, with two ends per bar or the fact that you might get two parts out of the first bar end. This tying of frequency to an order of magnitude denominator saves a lot of thrashing about to try to identify root cause.
What are some orders of magnitude that occur in your shop that you should consider for your problem-solving efforts on intermittent or periodic problems?
Material Order of Magnitude
Your shop processes have orders of magnitude, too.
Per Machining Operation
Per stock up
Per production order
How does this work? In a prior life, I had an intermittent customer complaint for a twisted square bar product. The customer was counting bad pieces cut from bars in bundles. The frequency was extremely low, it was not at one per bar or one per 10 bars, nor one per 20 bars. It turned out to be approximately, slightly less than “one piece per bundle.” Knowing that the frequency was that low, we were able to eliminate most of our upstream of bundle process steps. They would have generated much higher frequencies – more on the order of multiple occurrences per bar.
Based on our frequency being an approximate order of magnitude of one per bundle, we focused our investigation on the product and process at and after the bundle stage, which was where our problem occurred when a single bar end was being twisted by the movement of the last strapping and clip installation as it was tightened for packaging. The balance of the bar was held securely by the prior installed straps, but the tensioning unit grabbed one corner of a bar as it secured the final band around the bars, creating a twist in the end of the bar held under the tension of the clip that locked in that last strap.
Without comparing frequency of occurrence with orders of magnitude in our process, we would probably still be trying to figure out where in our process we could twist only one 14-inch segment out of 3,260 feet of bars. We’d be in denial, and eventually lose the customer.
If you have an intermittent or periodic problem with your products, start counting frequency of occurrence, and then figure out what the order of magnitude is compared with your process.
Ryan Kutz of PMPA member company Aztalan Engineering asks, “Since a better portion of our customers have adopted lean, just-in-time (JIT) or quick-response manufacturing practices where inventory is dock to stock and stock levels are managed daily, making inventory almost none existent, is there any evidence of this in the year-to-year trend? Are sales figures becoming even closer to real time with manufacturing orders?”
Ryan, we agree with your premise that most of our industry’s customers have adopted programs such as lean, JIT, quick-response manufacturing, and other dock-to-production (as opposed to dock-to-stock) programs. These programs are designed to reduce cost of possession for the OEM. However, we see these as being essentially a blunt instrument used to beat the supplier rather than as a means to truly coordinate supply-chain effectiveness. We feel that despite these programs, our OEM customers lack valid insight into market demand, causing inventories to rise and then their orders to our shops to plunge, concurrently. Take a look at the following chart from Dr. Ken Mayland that shows total business sales versus total business inventories:
These indicators tracked closely in 2014, but not so much in 2015.
This graph shows that in the first three quarters of 2014, our customers had a great handle on their demand and their orders and inventories tracked closely.
From the fourth quarter of 2014 forward, however, the percent change in total business inventories continued to remain in the positive year over year, while the percentage change in total sales year over year plummeted through end of Q1 2015, when they “leveled off” at around -2 to -3 percent.
I think we err when we overestimate the power of lean, JIT and quick-response manufacturing in the hands of our customers. These tools seem to be a blunt instrument, at best.
In reply to Ryan’s question, “Are sales figures becoming even closer to real time with manufacturing orders,” the graph above seems to show the change in sales and in inventories are converging at the end of 2015 and 2016 year to date.
My conclusion is that it doesn’t matter how fine a resolution our customers have in their lean, JIT, or quick-response manufacturing processes and procedures, if their ability to forecast is so poor, especially when the market declines.
Lousy forecasting by some OEM customers beats lean and JIT every time, leaving the OEM’s supply chain bloated with inventory and starving for releases.
Mechanical properties of a given steel under compression compare closely with its tensile properties. An “upset” can be performed to determine how the steel will perform under compressive load.
A brittle steel under compression will ultimately fail by breaking along cleavage lines at an angle approximately 30 degrees from the axis of pressure being applied.
A more ductile steel flattens out, rather than cleaving, showing vertical cracks around the outer circumference. This ductile steel will not break, but will continue to flatten as more stress (load or force) is applied.
This compression or upset test is helpful for assuring that steel will successfully cold work. It can also be used to determine the extent of seams, laps or other surface imperfections on the surface of the bar. That’s what I used to do when we were producing drawn wire for cold-heading applications.