HOME  |  NEWS  |  BLOGS  |  MESSAGES  |  FEATURES  |  VIDEOS  |  WEBINARS  |  INDUSTRIES  |  FOCUS ON FUNDAMENTALS
  |  REGISTER  |  LOGIN  |  HELP
Blogs
Guest Blogs
Fastener Inserts Designed for Lightweight Aerospace Materials Reduce Risks, Costs
12/27/2012

< Previous   Image 3 of 3   

Spiralock tapped holes are used in the gas turbine engine in this BMG-109 Tomahawk missile. (Source: Spiralock)
Spiralock tapped holes are used in the gas turbine engine in this BMG-109 Tomahawk missile.
(Source: Spiralock)

< Previous   Image 3 of 3   

Return to Article

View Comments: Oldest First|Newest First|Threaded View
Page 1/2  >  >>
Jerry dycus
User Rank
Gold
Fasteners in composites
Jerry dycus   12/27/2012 10:10:03 AM
NO RATINGS
 

              I'm not sure anything in this article is new as much if not all of it has been known for 50-100 yrs!!

              In composites one doesn't cut threads for either bolts or inserts if one is smart but instead molds them with epoxy, etc in place giving good holding and locking in many cases.  If a sandwiched material one hollows out the foam/etc core and fill it with epoxy to spead the load, then insert the bolt, insert, etc as needed.

              In other plastics drilling a smaller hole then screwing a hot bolt, insert into it  gives the needed strength in many cases.

              If higher loads than the local material can handle glue on a reinforcement piece with the threads built into it.

              As for working loose there are many types of thread lockers out there.

           

Cabe Atwell
User Rank
Blogger
Re: Fasteners in composites
Cabe Atwell   12/27/2012 3:57:26 PM
NO RATINGS
I use steel inserts in two cases. One where a bolt will be removed repeatedly, or I have to fix a stripped out hole. I think the later is where most inserts are used. In many cases the insert has a stronger holding potential versus the original thread. I only wish I could get some of the more exotic sizes cheaper.

C

Tim
User Rank
Platinum
Fasteners
Tim   12/28/2012 9:16:14 AM
NO RATINGS
The only issue that I have experienced with threaded inserts is the special tap needed for the OD of the insert. I have been in shops where they might only have one Helicoil tap for a certain ID thread. Production stops when the guy that keeps the tap in his tool box is on vacation.

ChasChas
User Rank
Platinum
Re: Fasteners in composites
ChasChas   12/28/2012 11:46:32 AM
NO RATINGS
 

This technology is a far cry from your Helicoil of yore. If you click the Spiralock link you will see the 30 degree "vibration stoppers", etc. Someone put some effort into this.

bobjengr
User Rank
Platinum
FASTENER INSERTS
bobjengr   12/28/2012 12:05:01 PM
NO RATINGS
Robert--very interesting post.  I think fastener technology has greatly improved over the last 20 or 25 years.  During my "tour of duty" in the Air Force, we would sweep the runways three times per day for components that actually fell off the aircraft.  It was amazing to me the parts we found.  Our sweeper had the capability of lifting a part weighing up to 100 pounds--and we found them.  Cowling, hundreds of screws and bolts, nuts, etc. you name it.  Believe it or not, we never had an accident, to the best of my knowledge,  as a result of components vibrating off but, I certainly don't know why not.  The technology has definitely advanced since those days--thankfully.

ironmandrake85
User Rank
Iron
Re: Fasteners in composites
ironmandrake85   12/28/2012 2:43:45 PM
NO RATINGS
Check out Nord-Lock. Spiralock doesn't even compare.

Nancy Golden
User Rank
Platinum
Apollo 13
Nancy Golden   12/29/2012 2:04:10 AM
NO RATINGS
This statement:  "A secondary issue arises: finding safe and reliable methods of fastening assemblies that can protect against fastener loosening while minimizing assembly and maintenance costs. These methods must provide complete assurance of joint integrity under the severe conditions of shock, vibration, and thermal cycling common in aerospace environments" brought to mind Apollo 13 - if I recall correctly the explosion was caused by a defective part off the assembly line. I would be a lot more interested in maximizing safety then in minimizing the costs of the fasteners...

Ann R. Thryft
User Rank
Blogger
Re: FASTENER INSERTS
Ann R. Thryft   2/25/2013 5:36:22 PM
NO RATINGS
bobjengr, that's a very scary story. How the heck could those aircraft fly after losing so many fasteners? What am I missing?

bobjengr
User Rank
Platinum
Re: FASTENER INSERTS
bobjengr   3/3/2013 5:48:47 PM
NO RATINGS
 Hello Ann, I asked the very same question and sometimes they did not.  There were times, granted not  many, when emergency landings had to be made due to cowlings or flight surfaces coming loose and vibrating uncontrollably during flight.   Of course, this can affect the airworthiness of the plane and consequently provide exceptional drag.  It was always amazing to me how uninvolved some pilots were relative to pre-flight inspections.    The "walk-arounds" recommended were sometimes cursory at best.   My experience was during Viet Nam and there were so many aircraft coming and going at the Ogden Air Material Area (OAMA) it was impossible to say what part belonged to what aircraft.    They were labeled with a date and placed in a special bin. Then you wait for a phone call.   

Ann R. Thryft
User Rank
Blogger
Re: FASTENER INSERTS
Ann R. Thryft   3/4/2013 1:23:46 PM
NO RATINGS
Thanks for the feeback, bobjengr. That's even scarier. Sounds like no one's paying enough attention, either to potential failures on individual planes, or to the entire system.

Page 1/2  >  >>
Partner Zone
More Blogs from Guest Blogs
While risk management sounds like one activity, in order to be conducted effectively, it must be broken down into three sub-components: risk assessment, risk monitoring, and response planning.
While many larger companies are still reluctant to rely on wireless networks to transmit important information in industrial settings, there is an increasing acceptance rate of the newer, more robust wireless options that are now available.
To those who have not stepped into additive manufacturing, get involved as soon as possible. This is for the benefit of your company. When the new innovations come out, you want to be ready to take advantage of them immediately, and that takes knowledge.
Design engineers will feel like kids in a candy store with the Cypress Semiconductor BLE Pioneer Kit. The development kit for low-power sensor-based systems is full of wireless wonder and exploration.
At the NPE2015 plastics expo this week in Orlando, Fla., Milliken & Co., a company that specializes in property-enhancing additives for polymers, is showing two products that are expected to have a major impact on their respective markets.
Design News Webinar Series
2/25/2015 11:00 a.m. California / 2:00 p.m. New York
12/11/2014 8:00 a.m. California / 11:00 a.m. New York
12/10/2014 8:00 a.m. California / 11:00 a.m. New York
3/31/2015 11:00 a.m. California / 2:00 p.m. New York
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Mar 30 - Apr3, Getting Hands-On with Cypress’ PSoC
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  67


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.
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Sponsored Content

Technology Marketplace

Copyright © 2015 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service