SJ’s Leading Technology - Tandem Mold and Stack Mold

来源:Engineering Department: Liu Songyun (Alias, Sam .Liu)发布时间:2014-01-08

In 2011, SJ Group successfully developed and manufactured nine sets of multi-cavity (4-cavity or 6-cavity) thin-wall In-Mold-Labeling (IML) molds and became a supplier of quality thin-wall molds preferred by Unilever, Jokey and other well-known global groups. As a result, SJ Group occupied a leading position in the thin-wall packaging mold industry.

In 2013, SJ Group successfully delivered 3 Tandem molds (1500*1300*1800mm) and 1 stack mode (2*16) to a customer from North America. The successful manufacture of these tandem molds and stack molds symbolizes that SJ Group has significantly upgraded its manufacturing from regular one-sided to multi-sided molds. It further proves the strength of SJ Group in high-end exported molds.

So far, SJ Group is one of the few successful Tandem mold manufacturers in South China. It is another major breakthrough of leading technology and manufacturing capacity after the development of the thin-wall molds. The success of these projects have played an immeasurable role for the SJ Group to develop the high-end mold market, as a milestone in the development history of SJ Molds.

What is Tandem Mold?

Tandem Mold (commonly known as Opening Stack Mold, hereinafter referred to as “T Mode”) is a technology born in Europe. So far in China and even Asia, only very few mold manufacturers are engaged in this technology, which is generally believed as a simple and effective means to improve the production efficiency. The core of T mold is to improve production capacity by the idling time during the injection molding period (or cooling period). To European and American countries with high labor costs, ultra-long injection period remains as the largest problem and also the key factor restraining competitive strength of an enterprise. Due to increasing HR costs proportion to operation costs of an enterprise in addition to higher automation, multi-cavity high-precision molds for export will have a large share in the international mold market, which is also the permanent goal of SJ.

What’s the difference between T Mold and Stack Mold?

Firstly, the largest difference between T- Mold and Stack Mold lies in the action of mold clamping and injection. T mold is opened alternatively by T lock that controls A and B mold joints. In addition, it can meet requirements of product injection molding for each mold joint with different molding parameters. (In the pictures below, the left is T mold and the right is the stack mold).

Secondly, T mold adopts a single manipulator to pick up alternatively on A and B molding joints. In contrast, stack mold shall simultaneously complete injection and mold clamping on A and B molding joints, so it adopts two manipulators or one manipulator with two clamps to pick up the products. As a result, T mold requires a narrower clamping distance from the hydraulic cutting presser, compared with stack mold.

Thirdly, cost of T mold is a little higher than that of stack mold. Generally, for similar products with one mold and multiple cavities, it is more economical to adopt the stack mold. In contrast, for multi-cavity molds with significant difference in product shape and wall thickness, it is suggested to select T mold structure for products with higher requirements. 


The following is the basic knowledge about T mold, which gives a general idea about the structure of the mold.

Precondition: The Tandem Mold Technology is suitable for the production of the technical parts with certain wall thickness, over 20 seconds of production period, the same materials, similar sizes or in pairs. According to actual technical conditions and equipment configuration, Tandem Mold Technology can improve production efficiency by about 60%.

Basic principles: Piece two identical or similar molds together and manufacture them on the same injection molding machine. Injection molding of the products is completed in Mold B with the cooling time of products in Mold A. By means of alternatively cycling, it can maximize the use efficiency of equipment. The technology of Tandem Mold, under similar production conditions, can save investment of molds and equipment by 30-40%, manufacturing costs by 40%, land occupation by 60%, equipment repair by 50% and the total cost by 40%.

Requirements on the Supporting Facilities of Tandem Mold:

Since T Mold enables to make two different molds on a single injection molding machine, the T Mold injection machine must have special controlling software to simultaneously handle two different injection parameters. In addition, the mold locking system requires larger mold space, wider template clearance and higher rigidity, compared with common benches. SJ Group has ordered 1000-t T Mold Machine from Guangzhou Borcher Machinery Co., Ltd. as one of the few largest special T mold or double-color injection molding machines in South China.

During the development of T Mold, we met much hardship and resistance and accumulated much valuable experience and lesson. Success of the project depended on high attention and input from the management of SJ and harmonious assistance by the vertical and horizontal departments. Acknowledgement should be hereby given to Mr. Wu of SJ Automotive and all the staff fighting for the project day and night. With pooled efforts, we won success in the development of T Mode and the trust of the customers on us.

The successful development of thin-wall molds, multi-cavity molds and T Molds does not mean that SJ Group has become the top mold manufacturer in the industry but at least proves that we are on the way to success.

To improve processing ability of the Company in processing hi-tech, precision and cutting-edge molds, SJ Group has purchased high-speed CNC and other top-class large equipment from ZEISS CMM and YASDA. With pooled efforts of all partners, we will surely become the top mold supplier in the industry.

Next:Walking in the United States
 Copyright@ SHOUJU INDUSTRIAL(GROUP) CO., LTD 粤08116890号2010-2013 All rights reserved