Procedure Title: ASSEMBLY OF A MOLD

Procedure Number: WIT-028

1.0 Purpose

To provide a systematic approach to the assembly and disassembly of a mold.

2.0 Scope

This procedure applies to all molds, new or used.

3.0 Responsibility

All employees working on assembly or disassembly of a mold.

4.0 Definitions

5.0 Procedure

5.1 Disassembly of a Mold:

5.1.1 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, marked containers, protective shielding, masking tape, aluminum prybar, plastic hammer and a strong light.

5.1.2 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. Get a box or boxes to put all the parts in and identify it with the proper job number.

5.1.3 Check for core pins in Ejector Housing and remove the core pins first.

5.1.4 Remove all necessary screws.

5.1.5 Remove Ejector Housing.

5.1.6 Remove screws from Ejector Plate.

5.17 Remove Ejector Back Plate.

5.1.8 Check if all pins are marked, if not mark as necessary.

5.1.9 Check if lift cores are marked, if not mark as necessary.

5.1.10 Remove all pins and parts from Ejector Housing. Protect all fragile parts and critical areas with masking tape.

5.1.11 Remove all water lines.

5.1.12 Remove all screws from cavity and core inserts.

5.1.13 Remove all slides and protect all critical areas with tape or carefully store in box.

5.1.14 Remove cavity and core from mold base by installing two or four extended screws in cavity and core. Knock out inserts by hitting screws. Place a piece of plywood in front of mold to prevent damage should the insert fall down. If difficult to remove, GET HELP.

5.1.15 Store all inserts in a manner so that all molding surfaces are protected and cannot be accidentally damaged.

5.2 Before Assembly:

5.2.1 Verify that all parts are cleaned, the workplace is organized and a strong light and magnification glass are at your disposal.

5.2.2 Verify that all surfaces that require polishing are polished, especially deep ribs.

5.2.3 Check for nicks, scratches, damaged edges or corners, chipped or damaged pins and damaged or loose pin holes.

5.2.4 All sharp edges inside cavity and cores (Ribs, bosses, corners, etc.) must be broken .010 Radius. Be careful not to break edges that must remain sharp. This is required to minimize stresses in plastic parts.

5.2.5 Verify that gate size is correct on all gates. On multicavity tools, gate size should not vary more then .0005 max.

5.2.6 Verify that all moving parts, such as ejector blades, slides, lift cores, etc. are of dissimilar material or nitrided to prevent galling.

5.2.7 Check base for correct markings, water fittings and pry bar slots between parting line, clamp plate, support plate and ejector plate.

5.2.8 Verify that all pins, sleeves and lift cores have the proper hole clearance, head clearance and proper depth clearance.

5.2.9 All pins, sleeves, lift cores and pass cores must be checked for proper length and correct position.

5.2.10 All pins, sleeves, lift cores and pass cores must be marked for proper location.

5.2.11 Check all pins and sleeves lead in clearance and lead in chamfer in core insert. Must be a smooth transition.

5.2.12 Verify that ejector pins in runner are shorter or rounded to aid in ejecting sub-gate.

5.2.13 Runner must be smooth and corners rounded.

5.2.14 Sub-gate must be blended in properly and sharp edges or corners must be smooth. (Sharp edges will shave plastic).

5.2.15 Check core, cavity, slides, runners, all deep ribs, pins, all gas traps, mold base for proper venting.

5.2.16 Assure that lift holes are in all plates, are of the proper size and are tapped as required. The size must be marked in bold letters and the lift bars must also be properly marked.

5.2.17 Check that ejector plate has tapped holes for pull back.

5.2.18 Lift bar, if required, must be marked with mold number.

5.2.19 Safety strap, if required, must be marked with mold number.

5.2.20 Check knock out holes for correct dimension and proper location.

5.2.21 Verify correct size of mounting holes and/or clamp slots for machine specified.

5.2.22 Verify installation and correct size for locating ring.

5.2.23 Check if sprue diameter is the right size.

5.2.24 Check if sprue radius is the right size.

5.2.25 Verify that water lines do not interfere with clamp slots.

5.2.26 All water lines must be marked in and out and numbered correctly.

5.2.27 Type of steel, Rockwell hardness, location and detail number must be marked on all details. All parts, including those parts that are interchangeable, will be identified for position in a way that assures the locations mark is always clearly visible even after assembly.

5.2.28 Assure that ID is engraved on cavities on multi-cavity molds.

5.2.29 Verify that part number is engraved.

5.2.30 Check that name plate is installed.

5.2.31 Verify that all mold components which have to shut off have been tested with a blued off transfer.

5.2.32 Check if latest revision pin is installed.

5.2.33 Demagnetize all components.

5.2.34 Check holes for waterplugs for smoothness, size and cleanliness. Lead in chamfer must have a smooth transition, round it with a buffing wheel if necessary.

5.2.35 Interlocking parts should have .0002 interference fit. This is a variable that may change from mold to mold.

5.2.36 Check that plastic part will not stick on wrong side of mold. Determine if undercuts are necessary.

5.2.37 Verify that sprue puller design will work as needed.

5.3 Assembly of a mold:

5.3.1 Verify that cavity, core, slides, mold base and all other applicable parts are clear of chips and any other foreign matter.

5.3.2 Check if all details are in place and match up by .001 or less. On interchangeable parts, all critical dimensions must be +/- .0001.

5.3.3 When mold is closed, check that there is still clearance between cavity and core retainer plates. This clearance should be .004 minimum. Caution ! If a runner is in cavity or core retainer plate, leave this section flush with cavity and core inserts and check if it impacts return pins. Return pins should make contact with A-side retainer plate.

5.3.4 Check if cavity and core inserts are higher than parting line, .004 minimum (.002 each above cavity and core retainer plate).

5.3.5 Verify proper lengths for ejector pins, core pins, sleeves, lift cores, return pins, pillars and all other mold components.

5.3.6 Check all holes for missing pins by looking in every hole of the assembled mold.

5.3.7 All slides, core pins, angle pins, cam locks and guide pins must be greased.

5.3.8 Check if core pins are installed in ejector housing and secured with retainer plate. Also check for proper pin clearance.

5.3.9 Core pins in ejector housing should be floating. Set screw can force core pin deeper thereby damaging the shoulder of core pin and core pin hole. Always use retainer plates.

5.3.10 Verify proper clearance on gibs in slide, up and down min. .002", left to right can vary.

5.3.11 Check if slides lock properly in slide retainer.

5.3.12 Verify that slides do not interfere with ejector pins. This is sometimes difficult to verify.

5.3.13 Check for proper clearance on cam pins, slides and cam locks when entering opposite side. Make sure pins don't bottom out.

5.3.14 Verify chamfers on all gibs, lamina and locks and that they clear the opposite side and the outside of mold base. Chamfers for water plugs must be rounded for smooth transition.

5.3.15 Verify that runner and gates are installed and tapered for proper break.

5.3.16 Verify preload of all pillars, .002 min, .004 max.

5.3.17 All limit switches must be orientated properly for wiring and function.

5.3.18 Check hydraulic cylinders for length of stroke.

5.3.19 Verify that slide locks and parting line locks function properly.

5.3.20 Check if insulator plates are installed.

5.3.21 Verify preload on return pins, +.001 to +.002 inch.

5.3.22 Check if return pins have to be spring loaded.

5.3.23 On hot sprue bushing, check if it is properly installed and assembled and electrical instruction is included. Make sure all components are installed and no wires are broken or damaged. Check that wire channel is in mold base and that clamps are in place to hold wires.

5.3.24 Check if sprue puller is installed.

5.3.25 Look at sprue puller pin and check if ejector stroke is long enough.

5.3.26 Check for proper sprue bushing length and fit. Is runner locked in place?

5.3.27 Make sure all screws are installed and tight. Follow a pattern to prevent missing a screw.

5.3.28 Water lines must be pressure tested, diversion plugs, "O" rings and correct jiffy connectors installed (Below surface up to .13 deep).

5.3.29 Move ejector plate back and forth to verify that it moves freely.

5.3.30 Push ejector plate forward and check if all pins, sleeves, lift cores and all other moving components spin freely.

5.3.31 With ejector plate forward, push ejector blades, sleeves, lift cores and all other moving components in and out to verify correct clearance.

5.3.32 With ejector plate forward, push ejector blades, sleeves, lift cores and all other moving components in and out to verify they are free and loose.

5.3.33 Check that ejector plate can use the full length of travel and has spring return if needed. Check if sprue puller clears.

5.3.34 Open and close mold on bench in a molding machine sequence to verify that the early return system functions properly. Check if slides clear ejector pins, lift cores and any other moving parts with sufficient clearance and that mold closes freely.

5.3.35 Check if ejector plate needs to be spring loaded. If return springs are installed in ejector plate, procedure 5.3.34 must be done first with the springs removed. After springs are installed check again for chipped ejector pins and also reassure that all pins and other moving components are moving freely per 5.3.30, 5.3.31 and 5.3.32. Use pry bars to force stripper plate forward. Hold the stripper plate forward by placing spacers between ejector plate and ejector housing. Ejector plate return springs should not be preloaded at all or only lightly, too much preload makes it difficult to install the ejector pins.

5.3.36 Verify that all necessary documentation is completed and ready to ship with the mold. Any deviations from noted tolerances must be marked in red and approved by the customer.

5.3.37 Mold, spare parts and other components must be properly secured for shipping.

5.4 Three Plate Molds:

5.4.1 Assure that all latches function properly.

5.4.2 Open and close mold on bench in a molding machine sequence to verify that latches latch and release properly. Hasco latches which lock stripper plates in place should have shoulder screws with a cushion stop installed, this will aid in absorbing the initial shock.

5.4.3 Verify that locked plate has .010 clearance when locked by latches.

5.4.4 If latches are secured by dowel pins, check that pins are fitted properly to prevent them from falling out when mold is in operation.

5.4.5 Assure that shoulder bolts are long enough to let runner drop through.

5.4.6 Verify that sucker pins are floating (Tight pins will wear out holes in floating plate).

5.4.7 Check that floating plate has cushion when stopping against shoulder screws (Use a steel washer and a hard rubber washer).