Plastic Injection Molding Parts

Plastic Injection Molding Parts

For 39 years Quashnick Tool Corporation has developed custom plastic mold for the who’s who of technology companies in the greater San Francisco Bay Area.
Knowing what’s at stake when it comes to developing and maintaining quality plastic injection molds and the plastic injection molding parts produced is the secret to their continued success. They realize that when companies begin new designs of molded materials, significant corporate R&D, engineering, manufacturing, administrative and support resources are at stake. Any redundant or rework efforts will add cost, delay time –to- market, and may upset medical device trials and qualification.
With this reality in mind they work with you to look as far ahead as possible in foreseeing and side-lining potential pitfalls in a successful molding program. Quality Pros think of it as it “FEMA” in action. They do this specifically by drawing from their 39 years of experience, merging extensive design and materials experience, with state of the art corporate management and sophisticated engineering and project management skills.
Whether you are looking to work with extremely tight time lines, wish to minimize development risks, want to keep manufacturing local in the greater Bay Area, or you are looking to save costs by building tools at a qualified QTC offshore partner, it pays to have a well versed and professional organization shepherd you through the process.
They’ve delivered success for several hundred companies in the greater Bay Area since 1971. They will deliver success for you.

What is your approach to resolving medical tooling and molding problems?

Answer:

It must be discerned whether the problem is with the materials or the molding before heading towards a resolution. For example, if there is a problem with a plastic part that is due to flash, then it is considered a tooling issue. However, if it is a material that is degraded (i.e. cracking or breaking) in the process of obtaining the parts, then it is a plastic materials problem.

In addition, providing examples of the product or specific examples of where the failure occurs is crucial to analyzing the problem. If it is a tooling problem, the program itself must be reviewed. It should be determined whether the material being used for the tool production is feasible for the particular task. The molding procedures should be assessed as well to see if the process is being done correctly.

Initially, the plastic used in the plastic mold should be properly dried and prepped prior to molding. The molding manager needs the qualifications necessary to run a material through to completion and handle it accordingly. The tooling must be designed for and capable of running the material specified. This includes the appropriate temperature controls (cooling and heating) as well as other specifics related to the material. Clearly defining the problem leads to a more effective resolution.

We realize that our success is wholly dependent upon the long term success of our customers and their continued business. We support our customers by maintaining  top quality engineering, customer service, tooling, molding and analytical capabilities- all under one roof.  Delivering results for over 35 years from our headquarters in Lodi California, Quashnick Tool makes this commitment to you:  we promise to add value to your program at every stage of the process!

Our Services

Quashnick tool is mold manufacturer china company provides engineering design, tooling manufacture and repair and injection molding production.

In-House Engineering

Engineering design:

We offer product design consulting to assure that your product design is optimized for cost and manufacturability. We offer mold flow analysis to assure it can be molded efficiently and without blemish or weakness. We then design tooling (molds) to make your part, even to the most demanding of specifications.

Since 1973

Tooling manufacture and repair (mold making and repair):

QTC has a full in-house machine shop/tool manufacture facility to support full DOMESTIC in-house manufacture and repair of molds. QTC maintains a seasoned staff of veteran tool makers bringing many years of experience to your project.

Quality Production

Injection molding production:

As a custom mold shop that has now added high volume medical component manufacture, QTC’s molding division maintains a full ISO 8 clean room injection molding manufacturing capability, in addition to standard injection molding operations.

 

Plastic Injection Molding

Plastic injection molding

Plastic injection molding is the process of injecting melted plastic resin, then forcing it under pressure into a plastic mold, where it cools and hardens.  The plastic mold is then opened, and the part is removed or “ejected”, usually automatically by “ejector pins”, long thin metal rods inside the mould that push through the cavity forcing the plastic part out of the mold cavity automatically as the molding machine opens the mold.

The plastic mold must have a very heavy wall thickness to keep the mold cavity from bulging since the plastic resin, is injected with as much as 20,000 pounds per square inch of pressure. And for the same reason molding machines must be able to clamp the mold shut with tremendous force.

On the top of the molding machine there is usually a hopper which is filled with the plastic resin to be molded, usually in the form of small pellets about 1/3 the size of a grain of rice.  The hopper feeds the pellets into the “barrel” of the machine.

The barrel has a long screw or auger inside, that rotates, forcing the pellets toward the front of the barrel.  The process of auguring the pellets produces a lot of heat, that melts the pellets. Additional heat is supplied to the barrel through the use of heating bands, electric resistance heating elements that wrap around the barrel.

At the end of the barrel there is a nozzle from which the melted plastic resin is ejected into the mold. The nozzle also has electric resistance heating bands wrapped around it.  The temperature of the nozzle is very important, and the temperature is monitored and controlled at the operator control panel.

If the nozzle temperature is not hot enough the plastic can “freeze off”, forming a solid plug that has to be removed before plastic can be injected into the mold.  If the nozzle is too hot, it can burn the resin destroying the plastic before it makes it into the mold.

Most injection molding machines can be run in either manual mode, or automatic mode.  In the manual mode, an operator slides open a door providing access to the mold itself. The operator reaches in and pulls the part out of the mold, then closes the door, and the mold closes, is filled with plastic, cools of for a few moments, and then opens up again. At that point the operator opens the door again, and the whole process repeats.

In automatic operation there is no operator.  The machine just hums along by itself, automatically ejecting the part or parts when the mold opens, and then re closing the mold, injecting the plastic etc.

Plastic injection molds can become quite complex. They usually require water lines to be built into the mold to cool of the melted plastic resin and harden the part, and they have ejector pins that push into the mold cavity as the mold opens, to eject the part out of the cavity.  Often the molded part requires moving metal pieces called “slides” that must pull metal cores out of areas of the part where there is no plastic such as the inside of pipe fittings etc.

There are many different brands and types of plastic injection molding machines that vary in the way they clamp the mold shut and other differences as well. What I’ve talked about is very very basic.

Solution for Plastic Mold heat treatment Issue

Solution for Plastic Mold heat treatment Issue

Plastic mold making failure mostly factors of heat treatment of this important aspect of. Because of the above heat treatment of general failure caused by improper accounting for about 50% of total failure mould. In order to give full play to the potential properties of mould steel, mould machining should be conducted after the quenching, tempering heat treatment in heat treatment, heating temperature, holding time, the length of the cooling speed of process parameter selection is not appropriate will be die failure factors. A machined good plastic mould,if lost due to improper heat treatment and its use value, is in the economy and the loss of time is very big, must adopt various measures to prevent mouth

Carbon and alloy elements with more influence of die steel of heating rate, poor thermal conductivity. So in the heat treatment (especially the quenching) heating speed not too fast, should be more slowly, to prevent mold deformation and cracking. Heating in air furnace quenching, in order to prevent oxidation and decarburization, using packing to protect heating, this heating speed is not fast, but the diathermy also slower, so won’t produce big thermal stress, relatively safe. In the use of salt bath furnace processing, mold heating speed fast, diathermy is also very fast, die inside and outside by thermal stress, if not properly controlled, it is easy to cause deformation or crack, resulting in failure of die, must be used to prevent or slow heating preheating acceleration

Plastic mold making will normally need heat treatment if you want the mold running over 1 million of life time shots

Die quenching effect of oxidation and decarburization is at very high temperatures, if not strictly controlled atmosphere, it is prone to oxidation and decarburization on the surface. But most die quenching, tempering after removal in local work surface grinding, the rest nearly no processing, therefore, oxidation and decarburization in heat treatment will also make the mold cause early failure. When the oxidation, mold surface easy to scratch, size, easy to produce fatigue crack in early use, when caused by decarburization, surface hardness significantly reduced resulting in early wear. plastic mold

In addition, decarburization mould surface after due to differences in inner and outer layer of tissue, cooling appear larger tissue stress often leads to quenching crack. In order to prevent oxidation and decarburization of mold can be used to protect the processing, packing box, filling materials filling anti oxidation and decarburization, sealed after heating. In addition, also can use salt bath furnace, controlled atmosphere furnace, vacuum furnace. Adopting the controlled atmosphere furnace must be strict control of carbon potential level of carbon potential is too low, will cause the same plastic mold surface decarburization, but carbon potential also cannot be too high, otherwise, although not happen decarburization, but often lead to make the surface of steel carburization embrittlement, which significantly reduce the fatigue strength of steel

Die casting manufacturer has the same issue during die casting mold making/

The quenching temperature effect of quenching temperature significantly influence the performance of various mold. The quenching temperature is too high, easy to grow up, and make a lot of carbide dissolution of the matrix, the formation of coarse needle martensite, make steel brittle, so die in use often cracking, chipping, breaking accident; on the contrary the quenching temperature is too low, the dissolution of carbide in the matrix is not full, the hardenability of steel worse, the quenching hardness is low, the use of no wear resistance, low life, at the same time, the compressive strength of steel is also low, prone to upsetting punch or drum and failure

Effect of the cooling conditions of quenching cooling condition. It is also very important. For different mould materials, should be organized according to state requirements, selection of different cooling rate. For high alloy steel, the alloy elements contain more, high hardenability, can the oil cooling, air cooling, even austempering and martempering processes such as, if adopts water cooling quenching is prone to rapid cooling quenching crack; for low alloy die steel, because of its lower hardenability, needs to use the water quenching cold can enhance the cooling speed, the general use of cooling water, if Liu Qi the oil cooling or air cooling, due to the low hardness after quenching, die do not wear, in service life shortened, also can cause early failure.

Plastic mold steel heat treatment have issue will effect Injection molding cost. Because the poor quality mold will effect the mold life and injection molding parts cost

Mould for manufacturing T10 carbon tool steel for cold impact annealing time, in actual use in the mold face many cracks and scrap. The observations show that the microstructure, two carbide in ferrite matrix on the distribution uneven, and there is a lot of graphite precipitated at the grain boundary. The analysis thinks, this kind of graphite by annealing thes teel in the temperature range of 780-800 DEG C when the insulation, long time caused by the.