خوش آمدید

Designing a Screw Barrel

When you are designing a screw barrel, you will need to take several factors into consideration. This includes the material, the dimensions, and the compression ratio. These factors can all have a direct impact on the final result. For example, the material melting temperature varies significantly among different plastic grades, so too high a temperature can ruin the material. To avoid this problem, a metering zone should be used to ensure the proper flow and distribution of the material through the barrel.
AutoCAD drawing

If you're making a screw barrel, you'll need to design it carefully. Generally, screw barrels are designed by machine manufacturers to suit a specific process. These manufacturers then share their screw barrel drawing with OEMs for their products. However, the OEMs might change the drawing in order to hide the machine's model or application.

You can download a free CAD file online from the web. The website features CAD files in various formats, including 2D DWG drawing and 3D CAD design. You can also download PDF files for free.
Material

Screws are used for dispersive mixing, which decreases the size of the smaller component in a given batch. The mixing function of the screw is very important to the overall quality of the part. Screws have several designs, but one common design is rectangular. Rectangular screws have rectangular slots with width and depth that are proportional to the diameter of the screw. Another design is a cone-shaped inner wall. Depending on the purpose, this may have an advantageous effect on the conveying rate of solids.

The material of the screw barrel is an important factor when choosing a screw. A screw's material is usually machinable steel. However, some screws have special treatments. They may have nitriding or hard coatings. These treatments will help delay wear of the barrel and flight surfaces.
Dimensions

A screw barrel is the cylindrical component in a screw extruder which houses the feed screw and provides a transfer medium for air, heat, and cooling. It is usually Injection Molding Machine Guide Road replacements made of hardened steel or other machinable alloy, with the inside diameter (D) being a larger number than the outside diameter (L). The length and diameter ratio L/D is used to specify the size of an extruder. The surface area of a barrel is directly proportional to the residence time of a material in the barrel.

The diameter of the screw and barrel are often the same, but the clearance between the screw flight and barrel increases with wear and in areas of high pressure. A 2.5-inch-diameter screw will have a 0.005" to 0.007" diameter clearance with a 0.003" radius.
Compression ratio

Compression ratio of screw barrel is the ratio between the screw length and screw diameter. This ratio varies from 20:1 to 34:1. The length of a screw depends on the number of sections in its design, the materials it processes, and the compression ratio of the screw. A conventional screw with three functional zones has an L/D ratio of about 24:1. A film casting screw needs a homogeneous melt, so it must have additional sections in its design.