My Steel Won’t Harden!

February 18, 2015

There are only a handful of things to check when your steel parts fail to respond to  quench and temper heat treatment.

Here’s my list in decreasing probability order:

Time, temperature, quench, suitable steel.

Time, temperature, quench, suitable steel.

  1. Mixed steel / wrong steel being heat treated.
  2. Decarburization on the surface.
  3. Failure to heat it above the austenitizing temperature.
  4. Failure to hold it for sufficient soaking time. (This can be especially problematic  with induction processes)
  5. Failure to quench fast enough.

So someone could say “Well you didn’t mention that the steel had a microstructure that  interfered with the process and is preventing us from getting the hardness required.”

To them I would say “Please see items 3 and 4 above.”

Photo credit Da Wei Induction Heating Machine Inc.

 

 


Why Tool Life Can Vary- Carbon and Alloy Steels

February 16, 2015

Tool life can vary when machining carbon and alloy steels despite the use of our best technology and our efforts to control our processes.

Many ways that tools can fail. this post discusses factors in the steel that can lead to this.

Many ways that tools can fail. This post discusses factors in the steel that can lead to this.

Here are 6 factors that can affect tool life in your shop.

  1. Variations between suppliers. Suppliers’ melt processes, scrap practices, melt recipes, and reduction in cold drawing and straightening practice can significantly affect the way that the chip breaks and resulting built up edge on tool and resulting surface finish. Even though the grade is the “same.”
  2. Variations in Chemistry.  A potential subset of variations between suppliers, the fact is that a plain carbon grade with 0.005 wt. % Sulfur  will not machine at all like the material with 0.025 wt% sulfur.
  3. Variations in grain size. While this factor is typically more relevant in stainless steels, when machining forgings, blocky structures resulting from excessive forging temperatures can result in inconsistent machining performance.
  4. Variations in microstructure. In this case, it is not so much about the grain size, as it is about the structure present. This is particularly problematic in the ~0.40 wt% carbon alloy grades like 4037.
  5. Decarburization or scaling on the work surface. Decarb can result is a carbon poor gummy surface, only to then transition into a fully carbon containing microstructure. Scale on the work surface can result in excessive tool wear, due to the very high hardnesses of the various iron oxides that may be present (Hematite, the red oxide of iron, Fe2O3, has a microhardness of approximately 1030 DPH.
  6. Deoxidation /High Inclusion Count. Free machining grades such as 12XX and 11XX steels are typically sold to a “Coarse Grain Practice” with no deliberate additions of grain refiners or deoxidizers. Sometimes, you may find deliberate additions of Silicon to 1144 in order to improve the internal soundness of the steel, the resulting silicates can abrade the edge of the tool when running at the surface feeds expected for a resulfurized steel. The addition of aluminum as a grain refiner can cause rapid edge wear as well. Rarely, very rarely, one might encounter exogenous inclusions entrapped in the steel from melt and casting. These can be real showstoppers.

Takeaway: Purchasing the same item from different suppliers hurls the full range of global variation at your machining operations. Standardizing on a single supplier for an item will allow you to get to steady state in your process.

Photo courtesy of via  CTE Magazine Plus

 


Adjusting to Unleaded-In Brass

February 9, 2015

Unleaded brasses are not necessarily harder to run than leaded brass. They are just different. By recognizing and accommodating for  their lack of Lead,  and the resultant different thermal conductivity, differences in chip forming, and the need to up-tool for  heavier feeds rather than higher speeds, your shop can also be successful at making parts from these newer, more challenging grades.

Same yellow color, Just no Lead in the Grain Boundaries

Same yellow color, just no Lead in the grain boundaries

It is widely established that Lead promotes machinability. To get the maximum production from automatic machines, additions of Lead have been commonly used in metals, particularly steels and brasses. In brass, dispersed in the grain boundaries, Lead acts as an internal lubricant- it reduces friction, and thus heat. By reducing the heat, Lead allows the metals to which it has been added to be machined at much higher speeds than the comparable non-leaded grades. These higher speeds [rpm or surface feet per minute (sfm)] result in shorter cycle times to produce each part. Short cycle times mean less expensive parts.

Leaded Brass offered these historical advantages

  • Excellent surface finish
  • Forgiving of machine mis-adjustments
  • No thermal issues
  • Fast cycle times
  • No chip control issues

When machining non leaded materials, we have to somehow maintain surface finish, get to commercially feasible cycle times, and deal with less than ideal chip characteristics.

What are some strategies for machining the new unleaded brasses?

Increase the feed. Since we lost the lead and the ability to run at higher speeds, increasing the feed can help us get to equivalent cubic inches of removal rates.

Improve the machine rigidity. Heavier feeds mean that your machine needs to be adjusted and solid. It also means more horsepower required- again mandating a rock-solid setup.

Improve the tool. 4 % lead is very forgiving of tool quality; The new nonleaded grades are the opposite, they present a number of challenges to your tools. Improved materials, geometry and coatings are key to machining unleaded brasses with minimum issues. also, they will require fewer replacements, helping to get more net production at the end of the shift.

Improve the chip management. some unleaded grades replace the lead with zinc, resulting in a grade with a type III chip- stringy and birds-nest prone. With these grades payespecioal attention to drills selected, and try inserts with chip control features to help you manage that chip.

Deal with the increased heat. The Lead helped to reduce friction and heat in the Leaded grades. with the lead removed, you will have increased heat generated. Carbide is more forgiving of heat, as are tool coatings. Talk to your supplier of Metal working fluids- Chances are that they will have a fluid that will help manage thiose extra BTU’s and maintain your tools’ edges.

Change your ideas about machining brass. unleaded brass machines more like steel than brass. as long as you think of it like leaded brass you will fight it. instead, think of it as just a yellow version of 1215 steel or stainless and your expectations will be much closer to reality.

Our cheat sheet for moving from leaded steel to unleaded steel provides a roadmap for adjusting to unleaded brass

Our cheat sheet for moving from leaded steel to unleaded steel provides a roadmap for adjusting to unleaded brass

Unleaded brasses are not necessarily harder to run than leaded brass. They are just different. By recognizing and accommodating for  their lack of Lead,  and the resultant different thermal conductivity, differences in chip forming, and the need to up tool for  heavier feeds rather than higher speeds, your shop can also be successful at making parts from these newer, more challenging grades.

The market for our precision machined parts continues to be evolve. Evolve your thinking and processing to adjust to the realities of unleaded materials to remain a viable and preferred supplier.

For more details on grades and recommendations, read our article Adjusting to Unleaded


ISM PMI Declines in January, Still Bodes Well for Manufacturing

February 3, 2015

The Institute for Supply Management (ISM) reported to day that the PMI for January
PMI was at 53.5%a decrease of 1.6% points from 55.1% in December. The employment index was at 54.1%, down 1.9 percentage points  from 56.0% in December. The New Orders Index  came in at 52.9 percent, a decrease of 4.9 percentage points from the seasonally adjusted reading of 57.8 percent in December.

These numbers are softer than we expected for January, but are still indicative of positive news for manufacturing- “Economic activity in the manufacturing sector expanded in January for the 20th consecutive month, and the overall economy grew for the 68th consecutive month, say the nation’s supply executives in the latest Manufacturing ISM® Report On Business®.”

Markets (industries) of interest to our shops  that reported growth in January 2015 included: Fabricated Metal Products; Electrical Equipment, Appliances & Components;  Transportation Equipment; Chemical Products; Machinery; Food,  Computer & Electronic Products.

For PMPA’s 2014 Year end summary of our Business Trends Index click here.

Calendar year 2014 was strong and steady until the final quarter with its seasonal and expected fall off.  Over 90% of respondents in December 2014 shared positive (same or improved) expectations for Net Sales, Lead Times, Employment, and Profitability for the first quarter of 2015.  With strong expectations in Automotive, Aerospace, Housing, and Medical Device Industry, we believe that the first quarter of 2014 will be a busy one for precision machining. – See more at: http://www.pmpa.org/news/latest-news/2015/01/22/business-trends-2014-review-and-summary#sthash.BXDQAFun.dpuf

We just came back from 5 days on the West Coast  visiting shops and sentiments were positive and optimistic except for the outlook for finding skilled workers.

Manufacturing continues to be a great place to be in the current economy.

ISMJan2015

Hat tip to Calculated Risk Blog for their Chart of ISM PMI


60 Years of Continuous Improvement- The Vanamatic Journey

January 22, 2015

It has been my pleasure to work with the folks at the Vanamatic Company since the late 1980’s as a  steel supplier technical representative, as a PMPA staffer, and as a friend.

A passion for improvement is what drives the folks Vanamatic.

A passion for improvement is what drives the folks Vanamatic.

I can say that over a big chunk of those 60 years, there were a few things that remained constant- fair dealings, honest communications, and an unrelenting focus on continuous improvement.

I was not at all surprised  when I got a call from Jeff saying that they were going to have something to announce and could I help them with it.

Of course there is something new at Vanamatic.

They are always working on ideas for improvement.

I was surprised when they told me it was a brand new website for the company’s 60th anniversary.

60 years was quite a surprise.

It has not been an easy time for manufacturing these last 60 years.

Frankly the last 8 years were pretty tough.

The Rise of China at the beginning of the new century wiped out a lot of the companies that were not very serious about their business.

Congratulations to Vanamatic for 60 years of leadership through continuous improvement. Improvement of people, process, and culture.

Oh, and improvement to the their online presence through their new website.

 


NIMS Announces Record Number of Metalworking Credentials issued in 2014

January 20, 2015

Credentials issued by NIMS in 2014 show that more students are preparing for success and high-demand careers.

NIMS%20Logo%20(R)

In 2014, NIMS issued 18,947 industry-recognized credentials, representing a 36% increase from 2013.

36% increase!

“It is clear that the precision manufacturing sector is strong and growing, and more students and workers are preparing for success in the wide variety of jobs our industry offers,” said Jim Wall, Executive Director, NIMS. “NIMS would like to congratulate more than 8,000 individuals who earned at least one industry-recognized credential last year and have the ‘mark of excellence’ that will make them highly sought-after talent.”

PMPA is a founding member of NIMS, and is pleased to see this success at credentialing talent to enter our high tech industry. Credentialing real people for in demand careers, developing standards and credentials, this is how we develop an advanced manufacturing workforce to sustain manufacturing in North America. As NIMS continues to upgrade and adapt the standards to our evolving technology, we have confidence that our credentialed new hires will be up to speed and able to safely add value on the first day of the job. NIMS standards are the basis for the Right Skills Now Program.

The National Institute for Metalworking Skills (NIMS) was formed in 1995 by the metalworking trade associations to develop and maintain a globally competitive American workforce. NIMS sets skills standards for the industry, certifies individual skills against the standards, and accredits training programs that meet NIMS quality requirements.

For more information on NIMS, visit NIMSREADY

For the full release on 2014 credentials earned, visit RELEASE

For information on Careers in Advanced Manufacturing check out our career blog at YOURCAREERFACTS

 


December ISM PMI Report- Beware the Bears!

January 13, 2015

There are a number of reasons that one could be bearish about the December ISM PMI report. But that doesn’t mean that we should be.

grizzly-bear duffle blog

“The December PMI® registered 55.5 percent, a decrease of 3.2 percentage points from November’s reading of 58.7 percent. The New Orders Index registered 57.3 percent, a decrease of 8.7 percentage points from the reading of 66 percent in November. The Production Index registered 58.8 percent, 5.6 percentage points below the November reading of 64.4 percent. The Employment Index registered 56.8 percent, an increase of 1.9 percentage points above the November reading of 54.9 percent. Inventories of raw materials registered 45.5 percent, a decrease of 6 percentage points from the November reading of 51.5 percent. The Prices Index registered 38.5 percent, down 6 percentage points from the November reading of 44.5 percent, indicating lower raw materials prices in December relative to November.”

 

test text

Actually, look how far above we are above the expansion / contraction line…

“The December PMI declined 3.2 percentage points from November,” roared the bear.

“The New Orders index dropped by 8.7 percentage points from November’s reading,” growled his sidekick.

“The Production Index fell 5.6 percentage points from November,” sang the Bear Chorus.

What are we to make of these Bearish indicators? Not much, really. Here’s why.

  • Its seasonal really. It is the end of the year. Companies are going to have to pay taxes on unsold inventory.
  • Yes it is below expectations. But does that tell us more about the PMI, or about the quality of the “expectations?”
  • 11 of 18 manufacturing industries reported growth in December. 

So please, before you order flowers and a sympathy card- consider this. The December reading above 50 indicates Manufacturing expansion for the  19th consecutive month, and by being above 43, an expansion of the US economy- for the 67th consecutive month.

P.S. Not to worry “The Employment Index registered 56.8 percent, an increase of 1.9 percentage points above the November reading of 54.9 percent. Inventories of raw materials registered 45.5 percent, a decrease of 6 percentage points from the November reading of 51.5 percent. The Prices Index registered 38.5 percent, down 6 percentage points from the November reading of 44.5 percent, indicating lower raw materials prices in December relative to November.” Stronger employment lower inventories, and lower material prices are all positives for Manufacturing.”

The decline in the  December 2014 PMI index is normal expectancy and nothing to worry about as I see it. Just look at the graph and all the other positive indicators.

Wave bye-bye, bear.

Wave bye-bye, bear.

 

Bear photo courtesy The Duffel Blog

Graph courtesy The Calculated Risk Blog

Waving bear link

 


Follow

Get every new post delivered to your Inbox.

Join 91 other followers