Submitted: July, 2006

Does anyone manufacture a device for splitting molds? We clean, or change over, between 15-20 molds a day and seem to spend too much time wrestling these molds apart with pry bars. Is there such a thing as a mold splitter?

You don’t say how large your molds are but generally anything over 5,000 lbs should be opened hydraulically with a mold splitter to save molds and backs.  Presently we know of a few companies that are working to address this need.

Enerpac (www.enerpac.com) 800-433-2766 is a hydraulics company that can build you one based on the size and type of molds you run. Some of these units are huge especially if you have 10 ton+ sized molds, but they work well.   

Another company, Die-Sep (www.die-sep.com) 877-967-9751 makes separators that not only opens the mold, but also flips the halves horizontally for easy access to clean, etc…

This system utilizes magnets instead of mechanical clamps to hold the mold halves to the platens.  A nice compact system. 

Yet another company worth researching is EAS  Mold & Die Change System Inc., with info available at http://www.easchangesystems.com. 

Now, regarding splitting molds the old fashioned (and most popular way)... Based on the experience of the ToolingDocs team, we have learned and taught techniques which help to improve the manner in which mold halves and also individual plates are separated (standing vertically) on the bench.  A few pointers will help make separating your plates easier and safer. 

The trick to hand splitting plates is not to bind the plate on the leader pins during removal.  Use plenty of lubricant (spray on type) and make sure your helper only applies steady pressure to his side while you do the bumping (on the opposite side) with your bar.  This is much easier than both of you attempting to bump the plates in unison…That just doesn’t work! 

Also:

• Make sure there are no dings or burrs on the bottom of the mold plates that can drag on the bench. Take a couple of minutes to file or stone (Norton combination stone) as necessary to smooth the plates.

• Utilizing bench parallels will reduce some of the drag on the bottom of plates as molds are opened, but if you routinely clean and smooth your bench top (280 grit paper on a 6” disk) parallels generally are not needed if the bottom of the mold is flat.

• Use the correct size pry bar. They come in 5 different sizes and lengths. Also, take 10 minutes and round over (medium file) the edges of your pry bars.  These come from the factory with sharp corners that will gouge the faces of plates and ding tooling.

• Keep several lengths of wooden 2 x 4’s, 2 x 6’s and 4 x 4’s handy under your bench to use for spacers when your pry bar alone won’t cover the span between plates.

• On small molds (2,000 lbs or less) turn the mold to face you.  This way one person can operate 2 pry bars simultaneously on a plate.

• In stubborn cases you might have to drive the leader pins back first. 

• You can also flip molds horizontally and utilize an overhead crane to lift the plates, if you have adequate bench space to lay the plates down and eyebolt holes in the sides of your plates for even lifting.

Hope these tips help, and if any ToolingDocs subscribers learn of any additional devices or methods, please drop us a line and we’ll ‘pry’ open the topic once more!