D I M O C O I N C
Mold Making
Department
We are capable of
engineering, designing, and building molds through out the range
of classification guidelines set by The Society of the Plastics Industry.
INTRODUCTION
The following classifications are guidelines to be used in
obtaining quotations and placing orders for uniform types of molds. It is our
desire through these classifications to help eliminate confusion in the mold
quote system and increase customer satisfaction. It is strongly recommended
that mold drawings be obtained before construction is started on any injection
mold. Even though parts may seem simple enough not to warrant a mold design, a
drawing showing sizes and steel types will pay for itself in event of mold
damage. These classifications are for mold specifications only and in no way
guarantee workmanship. It is very important that purchasers deal with
vendors whose workmanship standards and reliability are well proven. Mold
life, because of variations in part design and mold conditions, cannot be guaranteed.
This guide will attempt to give approximate cycles for each type of mold
excluding wear caused by material abrasion, poor mold maintenance and improper
molding technique. Maintenance is not the responsibility of the moldmaker.
Normal maintenance such as replacement of broken springs, broken ejector pins,
worn rings, or the rework of nicks and scratches should be borne by the molder.
Mold rework costs should be closely considered when deciding which
classification of mold is required. This document does not constitute a
warranty or guarantee by the Society of the Plastics Industry, Inc., or its
members for the classifications or specifications set forth herein.
CLASSIFICATION
OF INJECTION MOLDS UP TO 400 TONS
The following contains a brief synopsis of the various mold classifications and
the detailed descriptions of each mold class. Again, it is our recommendation
that a MOLD DATA SHEET (an example of which is in the back of the SPI
manual) be included with each request for quotation.
GENERAL
SPECIFICATIONS
1.
Customer to approve mold design prior to start of construction.
2. All
molds, with the exception of prototype, to have adequate channels for
temperature control.
3.
Wherever feasible, all details should be marked with steel type and Rockwell
hardness approximately .005 deep.
4.
Customer name, part number, and mold number should be steel stamped on mold.
5. All
molds should have eyebolt holes on the top side. There should be one above and
one below the parting line to facilitate mold removal, if required, in halves.
CLASS
101 MOLD
Cycles:
One million or more
Description:
Built for extremely high production. This is the highest priced mold and is
made with only the highest quality materials.
Detailed mold design required.
Mold base to be minimum hardness of 28 R/C.
Molding surfaces (cavities and cores) must be hardened to a
minimum of 48 R/C range. All other details, such as sub-inserts, slides, heel
blocks, gibs, wedge blocks, lifters, etc. should also be of hardened tool
steels.
Ejection should be guided.
Slides must have wear plates.
Temperature control provisions to be in cavities, cores and slide
cores wherever possible.
Over the life of a mold, corrosion in the cooling channels
decreases cooling efficiency thus degrading part quality and increasing cycle
time. It is therefore recommended that plates or inserts containing cooling
channels be of a corrosive resistant material or treated to prevent corrosion.
Parting line locks are required on all molds.
CLASS
102 MOLD
Cycles:
Not exceeding one million
Description:
Medium to high production mold, good for abrasive materials and/or parts
requiring close tolerances. This is a high quality, fairly high priced mold.
Detailed
mold design required.
Mold base to
be minimum hardness of 28 R/C.
Molding
surfaces should be hardened to a 48 R/C range. All other functional details
should be made and heat treated.
Temperature
control provisions to be directly in the cavities, cores, and slide cores
wherever possible.
Parting line
locks are recommended for all molds.
The
following items may or may not be required depending on the ultimate production
quantities anticipated. It is recommended that those items desired be made a
firm requirement for quoting purposes:
a.
Guided Ejection
b.
Slide Wear Plates
c.
Corrosive Resistant Temperature Control Channels
d.
Plated Cavities
CLASS
103 MOLD
*Cycles:
Under 500,000
Description:
Medium production mold. This is a very popular mold for low to medium
production needs. Most common price range.
Detailed
mold design recommended.
Mold base
must be minimum hardness of 8 R/C.
Cavity and
cores must be 28 R/C or higher.
All other
extras are optional.
CLASS
104 MOLD
*Cycles:
Under 100,000
Description:
Low production mold. Used only for limited production preferably with
non-abrasive materials. Low to moderate price range.
Mold design
recommended.
Mold base
can be of mild steel or aluminum.
Cavities can
be of aluminum, mild steel or any other agreed upon metal.
CLASS
105 MOLD
Cycles:
Not exceeding 500
Description:
Prototype only. This mold will be constructed in the least expensive manner
possible to produce a very limited quantity of prototype parts.
May be
constructed from cast metal or epoxy or any other material offering sufficient
strength to produce minimum prototype pieces.