One of my international contacts through the Syndicat International du Decolletage posted an intriguing photo on Facebook.
I did my best to try to figure it out, and eventually I came up with “entrepreurship.”
(By the way, the Facebook post was in Swedish…)
So I responded to my friend with “Entrepreneurship?” and waited to see how well I had done.
You be the judge. and by the way, don’t be too surprised to find out that you too, have the Gnosjöandan Spirit. Gnosjöandan Spirit
We are motivated by others’ success
We encourage cooperation
We are ambitious and dare being great
We are street smart
We are doers
We don’t overcomplicate things
We are generous and helpful
We are thrifty but never stingy
We dig where we stand
We are proud of the Gnosjö Spirit.
This reminded me a lot of the entrepreneurial spirit that we find in our shops. What do you think? Do you too, have the Gnosjöandan Spirit?
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:
Mixed steel / wrong steel being heat treated.
Decarburization on the surface.
Failure to heat it above the austenitizing temperature.
Failure to hold it for sufficient soaking time. (This can be especially problematic with induction processes)
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.
Tool life can vary when machining carbon and alloy steels despite the use of our best technology and our efforts to control our processes.
Here are 6 factors that can affect tool life in your shop.
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.”
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.
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.
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.
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.
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
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.
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.
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.
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: https://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.
Hat tip to Calculated Risk Blog for their Chart of ISM PMI