Days of Our Lives

Posted by stephens on Aug 31, 2010 in Automated Transactions, Engineering Decisions, Equations | 0 comments

My day is like a soap opera: one big meaningless drama that never seems to end. Let’s take one trivial example. I am tasked with creating an automated calculation in Excel that computes the number of days waiting for a job to get reviewed. The existing table had the start and end dates that are manually typed by the user. Simple enough. Like I always say,...

Read More

How to Counteract Unbalanced Thrust

Posted by stephens on Mar 20, 2010 in Engineering Decisions, Equations, Progressive Dies, Transfer Dies | 0 comments

The debate on how to counteract unbalanced thrust lives on in the stamping industry. I have seen it first hand in several markets. Automotive. Appliance. Medical device. The list goes on. Here is a note sent to me by one of my DieGuy.com readers through the contact page of this site: Hi Tim, Really enjoy reading up on your blog & your die knowledge. I have a...

Read More

Flanging Die Unbalanced Thrust

Posted by stephens on Mar 19, 2010 in Engineering Decisions, Equations | 0 comments

A while back, I blogged on how to quantify unbalanced thrust in cutting dies. Today, I would like to share the same for flanging dies. Forces in a flanging die are equal and opposite. So what happens when flanging occurs on one side of a cutting component? Unbalanced thrust. The issue with unbalanced thrust is should the flanging component be heeled or keyed to...

Read More

Cutting Die Unbalanced Thrust

Posted by stephens on Oct 16, 2009 in Engineering Decisions, Equations | 0 comments

Forces in a cutting die are equal and opposite. So what happens when cutting occurs on one side of a cutting component? Unbalanced thrust. The issue with unbalanced thrust is should the cutting component be heeled or keyed to counteract the lateral force. The first step to this decision is to quantify the magnitude of unbalanced thrust. The equation for...

Read More

Pad Travel with Die Mount Cams

Posted by stephens on Jul 17, 2009 in Cam Dies, Engineering Decisions, Equations, Tips & Techniques | 0 comments

The main pad in a die with die mount cams must hold the stamping in place on the lower tool during the press downstroke before the cam steels make initial contact. On the press upstroke, the main pad must hold the stamping on the lower tool until the cam steels clear the stamping. The simplest way to ensure the proper timing of the main pad when die mount cams...

Read More

Main Pad Travel with Aerial Cams

Posted by stephens on Jul 16, 2009 in Cam Dies, Engineering Decisions, Equations | 0 comments

The main pad in a die with aerial cams must hold the stamping in place on the lower tool during the press downstroke before the cam steels make initial contact. On the press upstroke, the main pad must hold the stamping on the lower tool until the cam steels clear the stamping. The simplest way to ensure the proper timing of the main pad when aerial cams are...

Read More

Die Mount Cam Slide Return Force

Posted by stephens on Jul 2, 2009 in Cam Dies, Engineering Decisions, Equations, Tips & Techniques | 0 comments

The required slide return force for die mount cams needs to be calculated to determine if a cam pad or auxiliary pressure system is needed for the application. This applies to commercial cam units and homemade die mount cams. The equation for die mount cam slide return force is: Fdsr = Fs + {(0.00981 • ms) • [0.20 • (cos β + sin β)]} where: Fdsr =...

Read More

Aerial Cam Slide Return Force

Posted by stephens on Jul 1, 2009 in Cam Dies, Engineering Decisions, Equations, Events, Tips & Techniques | 0 comments

In the spring of 1998, we witnessed an epidemic of commercial aerial cam unit failures in the field. These off-the-shelf cams were relatively new to the automotive industry, replacing the time-honored practice of engineering and constructing home-made aerial cams. We discovered that the cams were failing because the dies were engineered with no cam pad for...

Read More