Across the Bench - Let's Get To Work!

Separating Mold Plates

There are two methods used to separate mold plates. Vertically, with the mold plates standing on end, or horizontally, the mold laying down on the front or rear clamp plate. There is available machinery to mechanically separate large molds, but for this application we will discuss the two most commonly used bench methods.

Vertical Position
Advantages

• Visualizing—The mold is viewed and worked on as it runs in the press. Understanding mechanical movements during the maintenance stages (disassembly, troubleshooting, cleaning and assembly) is much easier and more accurate.
• Leadtime—Reduces repetitive handling of plates and tooling. With many molds, tooling can be cleaned while still in the plates.
• Troubleshooting—Suspect tooling can be located, removed, inspected or replaced more quickly, allowing for easier and more accurate troubleshooting.
• Inspection—Ejector and stripper plates can be actuated manually when checking for worn pins and bushings or sticking/binding issues.

• Improper bracing—The chance of the catastrophic domino death if plates are not braced properly, or if the technician works haphazardly.
• Awkward handling—Tall molds and rack systems are awkward to handle.

• Safety—There is no domino death here, but take care during assembly and verify tooling alignment in situations where the length of the tooling (cores, sleeves, etc.) is longer than the leader pins that engage and align mating plates.
• Ease—It is easier when dealing with tall or awkward molds with plates that vary in size or do not have flat bottoms on which to stand.

• Increased handling—Mold plates will need to be stood up to get the retaining plate off to access tooling, then these steps have to be reversed to assemble.
• More bench space required—Since mold plates are being removed lying down, they will require more bench space. Most benches can't accommodate total disassembly, meaning the four repair stages must be performed independently to mold halves.
• More confusion—It is very difficult to visualize mechanical movement accurately in complex molds.
• Plate alteration—Requires drilling and tapping eyebolt holes on opposing ends of plates, for balanced lifting.

C/R Review

• Current IML sheet performance statistics and pull reason
• Current last shot sheet for all observed product defects
• Current repair sheet for defect status, type, position and maintenance instructions
• Several past repair sheets for defect resolution effectiveness and last cleaning level
• The Tech Tips section of the manual for disassembly, cleaning or assembly procedures

Application

For example, when working on molds of six thousand pounds or less in the vertical position, run a stone across the bottom to remove any burrs or dings, blow out the waterlines and then set the mold directly on the bench—no parallels. Some technicians like to set molds on parallels, thinking that this makes the mold plates slide easier during disassembly/assembly. This also is how I was taught initially, but abandoned the idea when a toolmaker showed me that a braced, smooth plate slides just as easy on a flat, waxed bench-top. Also, it is much easier to reposition the plate allowing easy access to tooling or visual inspection. Using parallels limits plate movement, forcing you to lean over and twist your body around to see into counter bores and to work in awkward positions. You also will have a tendency to clean your bench less frequently, since the mold is up on the parallels, so your tools lie in crud.

Setting the mold on the bench and using a pry bar, separate the mold halves. Attention must be focused toward keeping the plates parallel as they are moved apart. Most experienced technicians can eyeball the distance and know where to apply the needed pressure to separate plates smoothly. Once separated, use the repair sheet and verify all blocked cavities and positions. If a cavity is blocked off and not recorded, stop and investigate why. After checking all cavities, observe the mold faces for vent residue level, the condition of the main leader pins, bushings, interlocks for grease level and signs of galling. This will tell you if the in-press servicing frequency (every seven days for this mold) is adequate to keep the frame tooling from drying out, the mold faces clean and if the mold halves dropped in the press from improper clamping.

If you are satisfied that all is well, continue to disassemble the ejector half of the mold until all plates are standing about two feet apart and supported by robust feet that will keep them upright as you move them around. At this point, check the repair sheet and determine what defects to correct first.