Impact Riveting uses impact force to permanently fasten components together. The quick process helps to minimize cycle time, increase throughput, and lower operating expenses. The most commonly used rivet for impact riveting is a mild steel semi-tubular rivet. The proper rivet geometry is crucial to meet the joint requirements.
Orbitform’s Lab Technicians have helped numerous customers assemble their parts in our Solution’s Lab and helped determine what fastener best fits their application. With over 30 years of experience, we have developed general guidelines to consider when choosing semi-tubular rivets.
There are three critical diameters to consider when choosing a semi-tubular rivet: head diameter, shank diameter, and end-hole diameter . The pull-out force required for the joint will determine the necessary head diameter. Soft materials will require larger diameter heads with greater surface areas to withstand pull-out forces.
The rivet shank diameter can be determined by comparing it to the thickness of the material stack up . Optimally, the ratio between the shank diameter and part thickness should between 1:1 and 1:3 for metal parts (closer to 1:1 for plastic parts).
Once the shank diameter has been determined, you can design the clearance hole to fit the rivet. This is important because too small of a hole can lead to rivet feeding issue or damage to the rivet or part. Generally, the clearance hole should be .010” to .015” larger than the shank diameter.
The rivet end-hole diameter should be about 70-80% of the shank diameter. Larger percentages mean the wall is thinner, which is easier to form and requires less force. However, this may also decrease the strength of the joint.
Another important consideration is the depth of the hole in the end of the rivet. The average depth is 100-125% of the end-hole diameter. Proper hole depth is necessary to prevent the rollset from hitting the body of the rivet and causing shank swell or rivet deformation.
Shank Length & Rivet Stick Out
The shank length is determined by the part stack up thickness and the required rivet stick-out . This stick-out is also known as clinch allowance and is generally between 50-55% of the shank diameter. If the rivet is too long, the parts may not be fastened together tightly. If the rivet is too short, there may not be enough material to clinch the parts together at all.
Mild steel rivets are the most common rivets used for impact riveting. However, different rivet materials may give very different results. For example, harder materials, such as stainless steel, require more force to form. This may increase the chances of shank swell and must be considered when determining shank length. It is vital to be aware of the hardness of rivets when designing parts and to determine the appropriate assembly equipment.
With over 30 years of manufacturing and assembly experience, our lab technicians and engineers have supported tens of thousands of assembly applications. Call us today for help determining the proper rivet size for your part, and let us assemble samples in our Solution’s Lab to ensure your part meets your requirements.
Posted: 09/26/2018 | by The Orbitform Blog Team | Posted in Orbitform Blog
With the current trend in the manufacturing industry and the upswing of the economy, manufacturers are struggling to find people to fill jobs and satisfy production requirements. Orbitform is no exception to this trend. Skilled trades workers are hard to find. Upon considering this challenge, Orbitform turned to a local competition for high school students to develop a plan on how to find qualified candidates to fill manufacturing openings.
iChallengeU is a two-week competition sponsored by Michigan Works Southeast, where students work with area teachers, corporate, civic and community leaders to develop solutions to real world problems currently being faced in manufacturing. Through research, evaluation and hands-on experience at a business location, a team of students present solutions at the end of the 2-week period in front of their respective companies and a board of outstanding community members.
This year, Orbitform asked students to answer the following question: “What are the strategies and tactics for filling the pipeline of hiring valid candidates?” The students worked diligently to learn about Orbitform and the local manufacturing atmosphere as well as to understand the challenge companies are experiencing with the lack of qualified applicants.
This group of five very talented students from surrounding schools in the Jackson area, came up with an amazing presentation on their findings, as well as suggestions for filling the pipeline of valid candidates for manufacturing. The team competed against seven groups, each having their own question to answer. With a very powerful and impressive presentation, the Orbitform Team tied for first place and won thousands of dollars in scholarships.
Skilled trades have been down-played for many years now and as a result, manufacturers are struggling to find qualified candidates. Before we reveal the team’s solutions to you, we challenge you to send us your ideas! Email us at firstname.lastname@example.org with your solution by Tuesday, October 2nd 2018 for a chance to win an Orbitform swag bag, and watch for our blog on Wednesday, October 3rd when we will announce the winner and present the iChallengeU team answers.
For more information on the iChallengeU program, or to become a partner and find a solution for your challenge, go to https://www.mwse.org/ichallengeu/.