Thin wall container mold
We manufacture thin wall mould, among other products.
Our company is producing a series of thin-wall moulds based on experience and knowledge. These moulds include
- spoon, fork and knife mould,
- thin-walled container mould,
- fast food box mould,
- thin wall bowl mould and
- other disposable thin wall moulds.
Nowadays, plastic containers are widely used in various applications, including food storage, snacks, oil packaging, and so on, from small to large, and can be found from 100 milliliters to 20 liters in size.
How to run thin wall injection molding
According to industry standards, thin wall parts using engineering resins have a wall thickness between 0.5mm and 1mm and a volumetric flow length to wall thickness ratio exceeding 75.
Amorphous resins, such as polycarbonate, challenge this definition, especially when used as engineering composites. Because a thinner wall section dissipates heat rapidly during injection, it changes processing, tool design, and part design rules. For this reason, the fill pressure will be up to 15,000-35,000 psi (100-240 MPa) and the fill time will be up to 0.75 seconds.
As a result of high fill pressures applied for short periods, mold equipment has to be capable of
- Pumps of high torque and accumulators are required for injection and clamping. The clamp force can be 4-6 tons/inch2 under fill pressures of 30,000 psi (200 MPa).
- High-precision sensors used to control hydraulic systems.
- Powerful machines whose platens are thick enough to prevent deflections to as little as 0.0005″ (0.013mm).
- The shot capacity can be limited to 40-70% by using a smaller barrel.
Tooling is affected by high pressure in the following ways
- The number of support pillars and the thickness of the plate(s) must be increased to prevent tool deflection.
- There needs to be more research on cavity-core shifting. The core may need to be interlocked to prevent shifting.
- Ventilation needs to be increased. Vaccum vents may facilitate faster fill speeds.
- In addition to numerous large gates, a melt-feed system that provides a high flow rate promotes easier filling.
- A hotrunner system is almost essential.
- Hardened tool steel of the highest quality must be used.
- To facilitate part ejection, ejector pins should have a large and numerous diameter (2x normal). Part ejection will be improved with low friction coatings.
- It is important that the entire tool has an equal thermal expansion.
Steel for thin wall mold
For thin-walled moulds, The steel material should also be considered carefully.
We recommend at least 718 steel for thin wall mould making about 800 thousand.
If a mirror finish is required, H-13(DIN 1.2344) steel will be recommended.
The plastic mould life will be 1-3 million, and the product’s surface will also keep the same finish.
P20 steel is widely used for normal mould making, but the mold must be made very strong because of the higher pressure of thin-walled injection moulding.
H-13(DIN 1.2344) and other hard steels add an extra safety factor to thin wall moulds.
However, the H13 thin wall mould cost may be higher than that of the standard mould by 30%-40%.
The increased cost is usually offset by increased production performance.
On the other hand, we will install a beryllium copper insert at the top of the core, with a depth of about 40mm, which can ensure better cooling to shorten the cycle time and allow customers to produce more products as quickly as possible.
In terms of the cooling system, we have our own ideas.
The diameter of the cooling channel and waterway layouts could assure the thin wall mould has the best cooling effect. Therefore, the thin-wall mould we made is of good quality, short cycle time, and fast delivery time.
If you want to make high-quality thin-walled moulds, look for China’s mould suppliers, Topworks plastic mold company will be your best choice.
You can get not only the quality thin-wall mould but also to get the best service.
Why thin wall mold get popular recently
A Guide to Success in Thin-Wall Molding
It is one of the most coveted capabilities for an injection molder due to the need for smaller, lighter parts. Currently, thin-wall refers to components with walls less than 1 mm thick. Large automotive parts may be considered thin if their walls are 2 mm thick. Regardless of the circumstances, thinner wall sections require a different processing approach: higher pressures and speeds, faster cooling times, and a change in the gate and ejection system. As a result, mold, machinery, and part design have all been affected by these process changes.
|STANDARD VS. THIN-WALL PROCESSING|
|Typical Wall, mm.||2-3||1.2-2||<1.2|
|Inject. Pressure, psi||9000-14,000||16,000-20,000||20,000-35,000|
|Hydraulic System||Standard||Standard||Accumulators on injection & clamp units. Servo valves.|
|Control System||Standard||Closed-loop on injection speed, hold pressure, decompression speed, screw rpm, backpressure, and all temperatures.||Same as at left, with resolution of 0.40 in. on speed, 14.5 psi on pressure, 0.004 in. on position, 0.01 sec on time, 1 rpm on rotation, 0.10 ton on clamp force, 2° F on temperature.|
|Fill Time, sec||>2||1-2||0.1-1|
|Cycle Time, sec||40-60||20-40||60-20|
|Tooling||Standard||Better venting, heavier construction, more ejector pins, better polish||Extreme venting, very heavy construction, mold interlocks, precise surface preparation, extensive ejection features, mold costs 30-40% higher than standard.|
Factors related to machinery
Make your molds tough!
- Use steel that is harder than P20 when dealing with aggressive thin-walled applications, especially when you anticipate high wear and erosion. Gate inserts made from H-13 steel and D-2 steel are very effective.
- An interlocking mold may be able to prevent flexing and misalignment.
- Telescoped cores can reduce the risk of core shifting and breaking.
- Put thicker support plates (often 2 to 3 inches thick) along with preloaded pillars (typically 0.005 inches) under the cavities and sprues.
- Reduce pin pushing by using larger and more ejector pins than conventional molds.
- Place sleeves and blades strategically.
- When rings and ribs are polished with diamond no. 2, sticking problems are eliminated. Mold release can also be improved with nickel-PTFE surface treatments.
- In addition to venting along the parting line around 30% of the parting line, vented core pins and ejector pins are also available for facilitating ventilation. Vents typically measure between 0.0008 and 0.0012 in. in depth and 0.200 to 0.0400 in. wide.
- The parting line may not normally need to be sealed with an O-ring, however, some processors do so to break a vacuum inside the cavity for gas evacuation.
- As injection speed increases, gates larger than the nominal walls decrease material shear and gate wear, maintaining good packing by preventing freeze-off before it occurs.
- A Rockwell (Rc) hardness of 55 or more is usually necessary for high injection pressure gates.
- In order to reduce stress at the gate, aid filling and prevent part damage when degating, use gate wells when gating directly onto a thin wall with a sprue, pinpoint, or hot-drop.
- It is possible to reduce pressure loss in runner systems by using hot manifolds, but they need at least 0.5-in. diameters. They should have smooth inner passages without dead zones. There should not be heaters inside the manifolds. Using valve gates, if necessary, must be non-restrictive and strong enough to handle high pressures.
- Mold surface temperatures should be as uniform as possible by placing non-looping cooling lines directly in the core and cavity blocks.
- To keep steel at a desired temperature, rather than decreasing coolant temperature, increase coolant flow through the tool. It is recommended that the cooling fluid temperature difference between delivery and return do not exceed 6° or 10° F.