What is the Ingate Sleeve?

The Ingate Sleeve is also called the nozzle, the nozzle, and the Ingate. It is a part of the runner that injects the molten plastic material from the nozzle of the injection molding machine into the mold and is used to connect the molding mold and the metal fittings of the injection molding machine.

Ingate sleeve manufacturing material

• SKD61 hot work dies steel can produce high-end and very durable sprue sleeves, and the hardness can reach 48~52HRC. The sprue sleeve made of SKD61 has the characteristics of high-temperature resistance and durability, and the quality of the formed product is excellent.

• SUJ2-bearing steel is a common manufacturing material for mid-end sprue sleeves, and the heat treatment hardness is about ±HRC52.

• S45C, the material used for low-end molds, must be sprayed with anti-rust oil and other anti-rust treatment after high temperatures to prevent rust.

• The nozzle made of hot work die steel has the characteristics of heat resistance, wear resistance, and durability, to prevent the leakage of plastic materials, the feed inlet is generally designed as an R-angle arc-shaped flow-type transition.

Ingate sleeve design

Since the Ingate has to contact and collide with high-temperature plastics and nozzles, the Ingate part of the mold is usually designed as a detachable and replaceable bush, referred to as the pouring sleeve or the Ingate sleeve, and the Ingate sleeve is also called the nozzle. The tapered hole in the Ingate sleeve is the first channel for the melt to enter the mold, called the Ingate.

To avoid repeated contact and collision between the Ingate and the high-temperature plastic and the nozzle, the Ingate bushing should generally be processed with high-quality steel and heat-treated. Generally, it is fixed on the formwork to prevent the Ingate sleeve from rotating or being taken out during production.

The role of Ingate sleeve

1. The Ingate won’t be staged in stages because it is convenient for mold fabrication.

2. The plastic melt in the barrel is injected into the mold as the primary channel of the gating system to make sure the melt enters the cavity smoothly.

While ensuring that the coagulation material in the main channel can be removed easily, it should be ensured that there is no overflow of plastic melt during the injection process.

Ingate sleeve classification

There are many forms of Ingate sleeves, which can be selected according to different mold structures. According to different gating systems, Ingate sleeves are usually divided into two types Ingate sleeves for two-plate molds and Ingate sleeves for three-plate molds. The large sprue gate refers to the Ingate sleeve used in the two-plate mold, and the fine sprue gate refers to the Ingate sleeve used in the three-plate mold.

Ingate sleeve used in the two-plate mold.

The Ingate sleeve of the two-plate mold is a standard part, which is usually selected according to the required plastic quality and the length of the Ingate sleeve required by the molded product. When the required plastic mass is large, use a larger Ingate sleeve, otherwise, use a smaller type.

Select different sprue tapers according to the length of the Ingate sleeve so that the hole diameter at the end of the Ingate sleeve can match the diameter of the sprue. In general, the diameter of the Ingate sleeve is selected according to the size of the mold base. If the mold base is less than 4040mm, choose the type with D=ф12mm (or φ1/2in).  The length is determined according to the size of the formwork.

Ingate sleeve used in the three-plate mold.

The Ingate sleeve of the three-plate mold is larger, the main channel is shorter, and the mold no longer needs a positioning ring. The Ingate sleeve of the three-plate mold must be separated from the runner push plate when the mold is opened, so they adopt a 90° conical surface fit to reduce mold opening and closing when friction, the diameter is the same as the sprue bushing of the second plate mold.

The influence of the Ingate on the workpiece and the selection of its position                          

Gate location requirements

• Appearance requirements (gate marks, weld lines)

• Product function requirements

• Mold processing requirements

• Warping deformation of the products

• The gate is not easy to remove

Impact on production and functionality

• Flow Length determines the injection pressure, clamping force, and whether the product is filled or not. The shortening of the full flow length can reduce the injection pressure and clamping force.

• The position of the gate will affect the holding pressure, the size of the holding pressure, and whether the holding pressure is balanced. Keep the gate away from the future stress position of the product (such as the bearing) to avoid residual stress.

• Venting must be considered at the position of the gate to avoid wind accumulation. Do not place the gate at the weak or embedded part of the product to avoid misalignment.

Selection skills of gate location

• Place the gate at the product’s thickest point so that pouring from there will have the best filling and pressure-holding effects.

• If there is insufficient packing, thinner parts will solidify more quickly than thicker areas.

• To avoid hysteresis or short shots, stay away from positioning the gate in areas with abrupt variations in thickness.

• The product can have an equal flow length if the gate is positioned in the middle of it.

• The needed injection pressure will change depending on the flow length.

• By ensuring that the holding pressure is consistent throughout, central pouring can prevent uneven volume shrinkage.

Gate of Ingate sleeve

The gate, which joins the runner and the mold cavity, is a brief groove with a modest cross-sectional area. To get the following results, the cross-sectional area should be small.

• The gate is chilly shortly after the mold cavity is injected.

• The water removal port is straightforward.

• When the dewatering port is finished, very little is left behind.

• Make it simpler to manage the filling of several mold cavities.

• Minimize the issue of excessive filler.

There are no hard and fast rules for designing gates, most of them are based on experience, but there are two basic elements that must be compromised.

• To minimize pressure loss when the plastic passes through, the gate’s cross-sectional area should be as large as possible, and the channel should be as short as possible.

• The gate needs to be small so that it can easily freeze and stop the flow of extra plastic. As a result, the gate is in the middle of the runner, and it should have a circular cross-section. The switch of the gate, however, is typically made by the module and controlled by the switch.

Gate Size

The gate’s length and cross-sectional area can be used to calculate its size. The ideal gate size can be determined by the following elements.

• Rubber flow characteristics.

• The thickness of the module.

• The amount of rubber injected into the cavity.

• Melting temperature.

• Die temperature.

When determining the position of the gate, the following principles should be adhered to

• The rubber injected into each part of the mold cavity should be as uniform as possible.

• The rubber injected into the mold should maintain a uniform and stable flow front at each stage of the injection process.

• The possible occurrence of welding marks, air bubbles, pits, voids, insufficient injection, and spraying of glue should be considered.