Bearings and transmission for extruders, injection molding machines, and mills in the plastics industry

Plastic extruders and injection molding machines operate with screws that rotate at medium speeds and support combined radial and axial loads. The bearings in these machines must withstand high temperatures due to proximity to the heated cylinder and contamination from molten polymer or particles.

In an extruder screw, the main bearing is usually cylindrical roller or angular contact ball bearings, depending on the design. In injection molding machines, the clamping system and injection carriage use deep groove ball bearings and linear bearings for precise movements.

Choosing the right bearing impacts productivity: a failure forces production to stop and the assembly to be disassembled. That's why at MR we work with recognized brands for this application and help you identify the exact reference for your machine.

Deep groove ball bearings are the most common in the plastics industry due to their ability to support moderate radial and axial loads in both directions. They are used in electric motors, vacuum pumps, fans, and gearboxes of extruders and injection molding machines.

At MR we supply a wide range of deep groove ball bearings, with references such as 6010, 6008, 6012, 6030, 6301, and 6202 from brands like SKF, FAG, and TIMKEN. These bearings can have seals or shields depending on the working environment.

For high-temperature or contaminated applications, versions with C3 internal clearance or special lubricants can be chosen. If you have the code or dimensions (inner, outer, and width), we can quote the appropriate option.

Plastic mills, which grind scrap or defective parts to reuse material, generate very high radial loads and vibrations. Cylindrical roller bearings are ideal because their design distributes the load along a contact line, supporting more than ball bearings.

At MR we work with cylindrical rollers such as N3055, RNU 305, SL182226, SL183018, 6217, and 5326 from SKF, FAG, and LINK-BELT. These references cover various shaft sizes and load capacities.

Additionally, split housings are often used in mills to facilitate assembly and disassembly. If you need to replace a bearing in a mill, send us a photo of the nameplate or the code, and we'll indicate the alternative.

Synchronous (toothed) belts are used in extruders and injection molding machines to transmit motion between the motor and screw, or in dosing and feeding systems. Their advantage is that they don't slip, maintaining a constant and synchronized transmission ratio.

At MR we supply synchronous belts from brands like SKF and DODGE, with references such as PHG 3L230, PHG AX31EP, HT250, and HT500. We also work with toothed pulleys for synchronous belts, allowing the complete assembly to be built.

When quoting a synchronous belt, it's key to indicate the pitch, width, and length (or number of teeth). If you have the used belt, a photo with the brand and code helps identify it.

V-belts are used in applications where vibration absorption and some slippage under overloads are required, such as in pumps, compressors, and some extruder drives. They are easy to maintain and economical.

At MR we work with pulleys and V-belts, including references such as PHP 6-B68TB and PHP 6-B86TB from SKF. We also supply cast iron and steel pulleys for various shaft diameters.

To quote, we need to know the belt profile (A, B, C, etc.), length, and number of pulley grooves. With that data, we'll provide the quote promptly.

Plastic injection molding machines use linear guides and ball screws for the movement of the injection carriage and clamping system. These components require high precision and rigidity to maintain the dimensional quality of molded parts.

At MR we supply linear motion products, such as guides, carriages, and screws, and couplings to connect motors to screws. We work with recognized brands and can advise you on selection based on load and stroke.

Flexible or rigid couplings are used to absorb misalignments and transmit torque without backlash. If you're assembling or repairing an injection molding machine, consult us for the linear and coupling assembly.

To quote any bearing or transmission component for extruders, injection molding machines, or mills, you can write to us via WhatsApp or email. Send us the part code (e.g., 6010 or N3055), dimensions (inner, outer, and width), or a photo of the part.

If you don't have the code, with the brand and model of the machine, we can help you identify the correct reference. We work with the main brands on the market and will provide the quote promptly.

We are in Buenos Aires, Argentina, and serve the entire plastics industry in the country. Don't hesitate to consult us for your specific need.