Thursday, March 8, 2007

Assembly and Disassembly Mold

The following is a good checklist for disassembly and assembly of a plastic injection mold. Some of our customers to not have trained moldmakers on staff to perform this kind of assembly and disassembly so we have listed a procedure here to help give your tooling room staff a good start, HOWEVER, this must be done at your own risk! We HIGHLY recomend that every molding facility should have skilled moldmaking professionals on staff to perform assemblies, disassemblies, maintenance, and repairs.



the picture at the top show disassembly various parts of mold
Disassembly:
• The mold must be placed on two rails on a clean table with sufficient space. Tools used must be in good condition and should include allen wrenches, aluminum prybars, rubber mallet, duct tape, and some containers.
• Separate mold at parting line carefully and look for any visible damage. If mold is damaged, report it at once. Check for rust in core and cavity and report it at once if found.
• Have containers to put all the parts in and identify it with the proper job number.
• Check for core pins in Ejector Housing (at the bottom clamp plate) and remove the core pins first.
• Remove all necessary screws in the Ejector Housing and remove it.
• Remove screws from the Ejector Plate and remove it.
• Check if all pins are marked, if not mark as necessary.
• Check if lift cores are marked, if not mark as necessary.
• Remove all pins and parts from Ejector Housing. Protect all fragile parts and critical areas with duct tape.
• Remove all water line jiffy-plugs
• Remove all slides assemblies and protect all critical areas with tape or carefully store in container.
• Remove the Sprue bushing, hot sprue, or any hot runner system.
• Remove all screws from cavity and core inserts and install two or four longer screws in cavity and core. Then knock out cavity and core inserts from mold base by hitting screws with a rubber, aluminum, or copper mallet. BE CAREFUL NOT to knock insert out onto the bench or floor and damage it. If you can't bump the insert out into your own hand GET HELP.
• Once the primary inserts are removed, remove all sub-inserts, gate inserts, core pins, etc. and protect all critical edges with tape or carefully store in container.
• Carefully clean all details with a clean, mild solvent and clean towels being careful NOT to damage sharp edges, parting surfaces, shutoffs, or the cavity finish.
• Finally, store all inserts in such a way that the molding surfaces are protected and cannot be accidentally damaged.



Finishing Assembly Picture
Assembly:
• Have all the mold plates, inserts, and components in one place ready for assembly. Have a clean table and two rails to slide plates on. Tools used must be in good condition and should include allen wrenches, aluminum prybars, rubber/copper/aluminum mallets.
• Cleanliness is critical in mold assembly. Make sure all plates, inserts, and components are clean and free from grit, debris, and chips. After you have carefully cleaned all details with a clean, mild solvent and clean towels THEN wipe everything again with your clean, bare hand to remove small grit (Careful NOT to damage sharp edges, parting surfaces, shutoffs, or the cavity finish)
• Install all sub-inserts, gate inserts, core pins, etc. into the primary inserts. Check that all inserts and pins are marked and that they are installed in the correct location and position.
• Mount the B-Plate to the Support Plate
• Install the B-Half insert set, any slide assemblies, and any other B-plate components. Check that all parts are marked and that they are installed in the correct location and position.
• Insert and grease all ejector pins, ejector sleeves, and ejector blades through the pin retainer plate, support plate, and core inserts. Install all return pins and springs. Install and grease any Lifter mechanisms. Bolt on the Ejector plate.
• Assemble the ejector housing, with support pillars, guided ejection pins, etc. Guide this assembly through the ejector & other plates and bolt it to the support plate. Insert any core pins that mount in the bottom clamp plate and fasten their backup plates. Lubricate the entire assembly.
• Verify that the Slide assembly moves freely, is greased, and that the slide retainer is functioning properly.
• Move the Ejector assembly forward and check if all pins, sleeves, lift cores and all other moving components spin freely. Wiggle to verify correct clearance and that all components move freely
• Check that ejector plate can use the full length of travel. Check if runner & part will clear the core when ejected.
• Mount the A-Plate to the top clamp plate
• Install A-Half insert set, heel blocks, angle pins, and any other A-plate components. Check that all parts are marked and that they are installed in the correct location and position.
• Install the locating ring & sprue bushing, check that sprue radius, and oriface are the correct size and verify that the sprue bushing is rotation locked and retained
• If the mold features 3-plate or hot runner system install them at this stage.
• For Three-Plate molds, verify that all latches function properly, that they latch and release in assembly, and that plate separation is sufficient to let both the part AND the runner drop through. Also check that all latch dowel pins are secured so as not to come loose during operation. Lubricate the whole assembly and verify that it moves freely.
• For Hot Runner molds check that all wiring is in a channel, free from damage, and free from possible "pinches" during assembly. Check continuity all all circuits
• Install all jiffy-connectors with teflon tape or suitable thread sealant and water test.
• Check all limit switches
• Spray with WD-40 and close the assembly
• Verify that the mold has a mold strap and that it is fastened correctly