Tooling for Injection Molds
Parts Design (client may provide completed 3D files)
The tooling process begins with a completed and
checked part design. Titoma can optionally optimize
your design for Design for Asian Manufacturing
(TM) before tooling in order to lower your costs
and ensure that your design will work well with
Parts Prototyping (if necessary)
If you would like to validate your parts design with
a machined piece that you can see and feel, Titoma
can use Computer Numerical Control (CNC) techniques
to prototype your parts.
At this stage the tool is designed, using the
information from your completed
Check and Mold Flow Analysis
The tool design is validated for correctness.
Tool Fabrication (including use of Computerized
Numerical Control (CNC) and Electrical Discharge
Machining (EDM) technologies)
The tool is precisely fabricated according to the
Shots To Client
Once the injection molds are made, the first test shot
samples will be sent out soon after via
international courier. Once sent, these
usually take around 2-5 days to arrive.
Modifications and Texturing
At this stage Titoma completes the tool and makes any required changes to bring the tool into the approved
spec. Changes made to bring the tool to spec (specifically excluding design changes,
which are always charged for) are made free of
charge by Titoma.
At this stage, texturing also takes place, which is
normally the last stage before mass production.
Mass Production Run or Export
At this stage parts are produced and delivered to
the customer, or the tool is released for export
Molding begins with tooling.
No matter how good the design, if
the tooling is not up to the task, the quality of the parts
The Molding Machine
consistent dimensions and quality requires up-to-date molding machines,
operating to specifications, with precise position and pressure control
capabilities. The basic construction of a molding machine is fairly straightforward:
Material is fed in through a hopper
into a screw and barrel where it is heated to a molten condition. The melt is
then injected under high pressure into the mold while the mold is
held closed with the high force of a toggle or hydraulic ram. The goal
is to melt resin in a very uniform and repeatable fashion, inject it
into the mold under very precise and repeatable pressure conditions, and
hold the steel temperatures in the entire flow system very stable. After
the molten plastic is solidified, the mold is opened and the gear is
ejected. It then continues to cool in the open air.
many handling and pre-processing requirements for injection molding materials. Engineering polymers
quite often must be dried to a specific dew point prior to use. When parts
are made, runners are formed that some shops regrind and put back in the
melt. This quite often raises more quality concerns than the slight
savings in material expense may justify, and CPIM uses only virgin
The method of injecting the plastic
into the mold is very important. In most cases the plastic should be
injected under high pressure very quickly in order to maintain the good
characteristics of the melt completely during injection. As the mold
cavity fills, the injection pressure should be held at the same high
value and the speed of injection slowed to maintain that pressure. At
the moment when the part is filled, and the mold machine switches over
from injection to a pack & hold condition, the plastic melt is held at
the same high pressure. This pressure is held for as long as it takes to
freeze the gates and achieve the highest weight possible for the molded
part. Below is a graphic image of the pressure and fill patterns of a
typical plastic molded part.
(Part is filled in 0.23 seconds)
- Magenta - Measured melt pressure
- Green - Programmed injection flow
- Yellow - Measured injection flow
Example of Tooling Process: Three Plate Tooling
Three plate tooling means that when the mold opens, three plates are separated. Between two
of the plates the plastic runner is ejected, and in the second space,
the plastic molded part is ejected.
Three plate tools allow parts
to be gated in the interior region of its body, which means that parts
are a significant step away from the turbulent region of injected
plastic flow. Melt temperature and pressure profiles are more uniform
which results in better molded part dimensional stability. These three
plate tools must be made with very high precision, and the gear cavity
should be replaceable since part shrinkage can never be completely known
before the tool is used to mold the gear.
Runner and part
configurations must be optimized for proper molding. Gate locations and
sizes are also critical. Mold temperature control is extremely
important. Every piece of steel in the vicinity of molten plastic should
be held at a constant determined temperature. Usually the mold base
should be insulated from the mold machine at its mounting points to
prevent uneven cooling from the large steel machine platens.
part ejection is also quite
important. Can pin ejectors be used without deforming the part?
Our normal payment schedule is 40% initial deposit, 30% on
First Shot, and 30% on approval.
For tooling, it usually takes 5 to 6 weeks from
receipt of deposit funds for molds to be made, assuming
that 3D files are correct. If you have a special urgent
request, we can reduce the lead time to 3 weeks (additional fees
"T1" samples are the first stage test shot samples
produced based on your 3D files. Depending on the
original 3D design and complexity of the plastic parts,
it takes usually one to two weeks, sometimes longer, to
complete the test shot stage.
production depends on parts
complexity and tool and material requirements, as well
as the quantities requested by the client. If you have a
dead-line to meet, please let us know. We will discuss
it with our factories to see whether it is possible to
meet your date. Usually we estimate 2 weeks for orders
of 10,000 units.
Please contact us for details on exactly how long your
project will take, as times (and project scopes) vary
Shipment times depend on which shipment method is used (i.e. DHL, UPS,
FedEx, TNT, air cargo or sea shipment).
Our prices are
quoted FOB China or FOB Taiwan.
If you have appointed a freight forwarder, we can use your
account and existing agreements for a nominal fee.
If do not have a specific forwarder, we can provide
names of forwarders we have worked with in the past.
Based on our experience, depending on the final
destination, it samples usually take about 2-5 days via
international courier, 2-5 days by air and 20-45
days by sea.
When deliveries are sent FOB China, international courier
service is not usually recommended as procedures can
be complicated. EMS is an alternative for small quantity
if the delivery is urgent, however.
Additionally, standard times for custom declarations
country to country. Please check with your local
freight forwarders service.