Plastic pot injection molding design

Plastic pot injection molding design


At present, there is an increasing demand for plastic flower pot moulds on the market. YuanCheng Mold’s R&D department is dedicated to researching plastic pot injection molding design. Examples include rattan flower pot moulds, nursery pot moulds, flower pot family moulds, and many more.

There are a number of advantages to using plastic flower pots, including their light weight, the fact that they can be turned into many colors, the fact they are corrosion resistant, the fact they can be manufactured conveniently, and the fact that they are affordable. This is a great replacement for flower pots that need to be replaced. However, the customer was worried about the hot runner in the long run.


Although the choice of a hot runner increases the total cost of the machine in the short term, in order to reduce the amount of aggregate waste in the production process. In the long run, the cost of the whole process will be reduced because the hot runner reduces the amount of aggregate waste.

Figure 1 Plastic Pot Injection Molding Design

Plastic pot injection molding design solution:

Plastic product analysis


An excellent resin variety after nylon, polypropylene (PP plastic) is a crystalline linear polymer with excellent features including high density, no side chains, and high knots. Polyethylene is white and translucent, waxy, and light in color. 

Also, it has more transparency than polyethylene. It is stiffer. Because it’s suitable for use in plastic buckets and basins, it’s chosen as a material for them.

Figure 2 Plastic pot injection molding design materials

Mold structure design

Figure 3 Plastic pot injection molding design

Figure 3: Plastic pot injection molding design

The gate and ejection mechanism are push plate types. One mold has two cavities, two plates, and one gate. It contains information about the mold gate’s position and type. Selecting hot and cold runners, designing the core cavity and ejection system.

Plastic pot injection molding design selections

Selection of gate location

Gate position is relatively strict during mold design. It is crucial to select the right grid for plastic parts. If you’re choosing a grid, be sure to avoid injection defects on plastic parts; cavity exhaust is facilitated; consider the load conditions; consider the position and number of gates; prevent the cavity or insert from being squeezed and deformed; consider plastic part molding size. On this basis, the pouring position is established below the plastic part.

Selection of gate type

Figure 4 Selection of gate type

Gates come in three types: straight, side, and point. With short strokes, small pressure losses and easy molding, straight sprues are easy to mold. Air bubbles can easily form during the long process, affecting the quality of plastic parts. Flow rates are higher with point gates, temperatures are higher, and they have a smooth surface and clear shape. Mold gates can automatically be broken after opening. It has disadvantages like mold structure and injection pressure. There must be little pressure loss for the plastic parts of the flowerpot.

Selection of runner type

There are two methods of injection molding plastic products. Injection molds use cold runners because after injection molding, the runner coagulates and needs to be removed. Hot runners keep the plastic in a molten state so that there is no waste created by condensate removal. A major consideration should be the cost of hot and cold runners, as flower pots have much plastic, so hot runners are designed to reduce costs.

Plastic pot injection molding design of cavity

Figure 5 Plastic pot injection molding design of cavity

Several types of injection mold cores (cavities) exist. The combined mosaic core (cavity) is more suitable for complex structures since it consumes more tool steel and is more difficult to work. But it’s less strong and harder to process. It is common to use a cavity design for flowerpot injection molds. Using a spiral cooling water circuit (type of cavity and core integration) to improve cooling efficiency.

Plastic pot injection molding design of ejection system

Figure 6 Plastic pot injection molding design of ejection systemPlastic pot injection molding design

Considering the relatively simple structure of the plastic part itself, a push plate type ejection system using air blowing is used. It has a large ejection area and strong ejection force without obvious traces of ejection. After blowing up the loose gap, the product is manually removed.


In this study, we mainly focus on the design of injection mold for flower pots. Including the design and selection of the gate system, runner, core cavity, and ejection system of the flower pot injection mold. 

Under mass production, it saves money to set the gate in the middle; the gate type is straight, and the runner type is hot. A spiral cooling water circuit has been designed and designed. The ejection system is push plate type, with a large ejection area and force. As soon as the design is finalized, the mold structure is reasonable, and the plastic parts produced can meet the needs of the application.

At YuanCheng Mold, we provide you with customised flower pot moulds and a one-stop service.

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