Shrinkage sag is a common phenomenon in injection molding, also in the producing process of plastic products. NINGBO LISONG INJECTION MOLDING TECHNOLOGY CO.,LTD is one of the leading manufacturer in wholesale Injection molding machine for disposable spoon and we have rich experience in dealing with this problem. In this article, we will analyse the main reason and give useful method to solve this question.   

Disposable spoon are widely found in our daily life, and with the development of take-out food industry the command of disposable spoon also increase rapidly. But shrinkage causes low quality  products and results in large losses. So it is critical to prevent the shrinkage during the producing process and then we need learn the reason why injection molding machine for disposable spoon produce shrinkage spoons.

There are four aspects that cause the shrinkage happening in the injection molding process, including injection molding machine, mould, the raw ingredient of plastic and processing.

Injection molding machine

Too big nozzle hole causes melted material flowing back and resulting in shrinkage while too small nozzle hole with a powerful resistance and insufficient ingredient results shrinkage also.

Lack of clamping force causes flaps to shrink, therefore it is important to check the mode-locking system before operating the machine.

To choose the machine with large plasticizing quantity if plasticizing quantity is insufficient. And check whether the screw and barrel wear.

In short, we must be cautious about the maintenance of machine and the accessories and inspect every part from mold designing to injecting to produce higher quality plastic products.

Mould

To make sure the thickness of products uniformly when designing the mould as uneven thickness will cause products shrinkage. 

To ensure the temperature are well-distributed when cooling and heating the products as uneven temperature will result in shrinkage.

To make sure the gating system is unobstructed and the resistance should not be too strong which means to ensure the size of the main stream should be appropriate with sufficient smooth.

For thin products, the temperature should be increased to ensure smooth material, and for thick products, the mold temperature should be reduced.

To ensure the gate opens symmetrically, as far as possible toward the parts of thick wall and to increase the volume of cold well

The raw ingredient of plastic
  

Crystalline plastics are more likely to shrink than non - crystalline plastics so we should add the raw material appropriately in process or add agent into plastic material to accelerate the speed of crystallization and at the same time reduce shrinkage.

Process

A high temperature in the charging barrel cause a large change in volume especially the front furnace temperature. However, we should increase the temperature appropriately for plastics with a poor mobility to make sure the smooth of flowing.

Too low injection pressure, speed, back pressure as well as too short injection time cause shrinkage.

For those that haven’t too much strict requirement in precision, when their outer layer is basically condensed and hardened while the inner part is still soft as soon as possible to let them out of the machine and leave them naturally cooling in the air. The method makes the shrinkage smooth and even negligible.

Trends of plastic or disposable spoon

There are so many people who look down the prospect of disposable spoon. But actually disposable cutlery has emerged as the most economical and efficient solution for both indoor and outdoor food service activities. Future Market Insights (FMI) in a new study has forecast the market to exhibit 0.9% Y-o-Y growth in 2021, after exhibiting negative returns in 2020. 

Use of disposable cutleries in hotels, pubs, bars and beyond has been a key game changer. For instance, these cutleries are highly sought-after for better convenience and hygiene factor in schools & offices. The convenient use and affordable pricing of disposable cutlery with availability of dispensed and wrapped types are driving growth.

Disposable spoons are expected to remain highly sought after. While plastic still accounts for majority of disposable spoons sold worldwide, consumers are gradually transitioning towards wooden spoons. Use and throw wooden spoons are widespread in countries such as India, France, and others that have implemented stringent regulations against the use of plastic.

Therefore you don't worry about the future of disposable cutleries. By the way if you have any need please feel free to contact us. NINGBO LISONG INJECTION MOLDING TECHNOLOGY CO.,LTD is one of the leading wholesale Injection molding machine for disposable spoon wholesaler and manufacturer and supplier and exporter and factory and exporter in China,welcome to bulk customized buy Injection molding machine for disposable spoon for sale.