HOME  |  NEWS  |  BLOGS  |  MESSAGES  |  FEATURES  |  VIDEOS  |  WEBINARS  |  INDUSTRIES  |  FOCUS ON FUNDAMENTALS
REGISTER   |   LOGIN   |   HELP
News
Materials & Assembly

More Than Cars Drive Powder Metals

NO RATINGS
Page 1 / 4 Next >
View Comments: Newest First|Oldest First|Threaded View
Page 1/2  >  >>
Ann R. Thryft
User Rank
Blogger
Re: Impregnation
Ann R. Thryft   9/11/2012 1:00:28 PM
NO RATINGS
Thanks, Greg. So it sounds like you've found that, for your needs, PM is good for certain moderate-load, both structural and impact, designs. What I still find interesting is the fact that there are so many automotive parts made with PM with high tensile and yield strength, and that PM use is also increasing in aerospace.

Greg M. Jung
User Rank
Platinum
Re: Impregnation
Greg M. Jung   9/7/2012 10:28:13 PM
NO RATINGS
Yes, for relatively moderate structural loads that are well within the strength limits of the PM material.  For example, PM oil-impregnated bronze bearings work well supporting the sliding portion of a lamp mechanism on an electroless nickel plated steel rod.   Designed properly, PM can successfully be applied to a wide variety of moving part designs.

Ann R. Thryft
User Rank
Blogger
Re: Impregnation
Ann R. Thryft   9/7/2012 11:38:22 AM
NO RATINGS
You said that you're favoring PM for some parts that don't have heavy impact loads. Do these parts have structural loads?

Greg M. Jung
User Rank
Platinum
Re: Impregnation
Greg M. Jung   9/5/2012 9:41:33 PM
NO RATINGS
Ann, I think Dave was spot on when he stated "if a part is not properly designed, it won't work, no matter how well it is made"  For many of our medical and electro-mechanical parts (that do not have  significant impact loads) we have great success when using an oil-impregnated sintered bronze as a low-cost bearing.  Tooling and piece part costs are low and tolerances are very good (assuming a good supplier with consistent process control).  However, not every design is suited for powder metal and we use a combination of design experience and historical application to guide us when to use the powder metal process.

Ann R. Thryft
User Rank
Blogger
Re: Impregnation
Ann R. Thryft   9/5/2012 12:16:16 PM
NO RATINGS
Greg, thanks for that input from the field. Do you have any comments about the differences between PM and cast metal along the lines of what Dave said below?

Greg M. Jung
User Rank
Platinum
Impregnation
Greg M. Jung   9/1/2012 10:46:38 PM
NO RATINGS
For our moving mechanism designs, I really appreciate the porosity of powder metal which allows us to impregnate oils in the material matrix.  This gives us a great low-cost, durable bearing with relatively good tolerances.

Ann R. Thryft
User Rank
Blogger
Re: Cost and mechanical properties
Ann R. Thryft   8/9/2012 4:07:05 PM
NO RATINGS
Dave, thanks for that observation. I think you're right--we tend to blame materials quality first, design quality second, when in fact the opposite may be true, or even both may be faulty.

Dave Palmer
User Rank
Platinum
Re: Cost and mechanical properties
Dave Palmer   8/3/2012 2:41:12 PM
NO RATINGS
@Ann: You bring up a good point -- the relationship between design and quality.

To me, "low-quality PM parts" are parts that are poorly compacted, poorly sintered, cracked prior to sintering, or made using contaminated powder.  The good news is that these are all problems that can (potentially) be fixed.  Process the material correctly, and the part will work.  

On the other hand, if a part is not properly designed, it won't work, no matter how well it is made.  For example, using a PM part in an application which involves significant impact loads is almost always a bad idea.

Sometimes the presence of a quality defect may lead you to believe that you're dealing with the first situation, when you're actually dealing with the second.

Ann R. Thryft
User Rank
Blogger
Re: Cost and mechanical properties
Ann R. Thryft   8/3/2012 12:36:29 PM
NO RATINGS
Dave, I know what you mean about low-quality PM parts. I've been on the receiving end of low-quality cast parts (and probably also low-quality PM; I find those harder to identify visually or tactually). My operating principle as a consumer is either it's the design or the materials or the combination that makes a bad part. You can also accuse QC, but QC may only be able to notice whether the duck walks and quacks like it's supposed to, not whether it breaks because it's actually a badly designed goose. That said, I was impressed at what PM can do when it's done right.

Dave Palmer
User Rank
Platinum
Re: Cost and mechanical properties
Dave Palmer   8/2/2012 5:36:53 PM
NO RATINGS
@Ann: I got my start as a process engineer in an investment casting foundry, so I have a certain bias in favor of casting and against PM.  I suspect that most people tend to be biased towards materials and processes they are familiar with.  I'm aware that it's a bias, and try to keep an open mind.

Unfortunately, this bias has been confirmed to some extent by bad experiences with PM parts.  These bad experiences were mostly due to designs which didn't take the nature of the PM material or the limitations of the PM process into account.

Of course, you could say the same about casting, or any other process.  Designers ignore the limitations of manufacturing processes at their own risk.

Page 1/2  >  >>
Partner Zone
Latest Analysis
The National Highway Traffic Safety Administration’s recent backup camera mandate could open the door to more vehicle innovations, including better graphical displays, 360-degree camera views, and the increased use of Ethernet.
With support from National Instruments, a group of dedicated students from Connally High School in Austin, where more than 50% of the students are at risk of not graduating, have created a successful robotics team that is competing in the FIRST World Championships.
Solar Impulse 2 -- a 100% solar-powered airplane -- has been completed. It features several advanced materials, some developed specifically for next year's attempted around-the-world flight.
Sherlock Ohms highlights stories told by engineers who have used their deductive reasoning and technical prowess to troubleshoot and solve the most perplexing engineering mysteries.
Lumus and eyeSight have partnered to create consumer-grade devices that offer all the prime functions of smart glasses without the bulk.
More:Blogs|News
Design News Webinar Series
3/27/2014 11:00 a.m. California / 2:00 p.m. New York / 7:00 p.m. London
2/27/2014 11:00 a.m. California / 2:00 p.m. New York / 7:00 p.m. London
12/18/2013 Available On Demand
11/20/2013 Available On Demand
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Apr 21 - 25, Creating & Testing Your First RTOS Application Using MQX
SEMESTERS: 1  |  2  |  3  |  4  |  5


Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.
Next Class: April 29 - Day 1
Sponsored by maxon precision motors
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Sponsored Content

Technology Marketplace

Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)
Copyright © 2014 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service