Accumulator blow molders employ a type of blow molding process called intermittent extrusion blow molding. These machines are similar to continuous extrusion blow molder machines except that the plastic that exits the extruder first builds up in an accumulator head before a hydraulic system pushes the accumulated plastic out through the die to form the parison. The two halves of the mold are clamped around the parison which is blown with air into the form of the mold. This system is ideal for larger and heavier products in which the weight of the parison tends to cause a large amount of pull upon exiting the die head, thus creating forces that lead to non-uniform wall thickness. Allowing the plastic to accumulate first and then get rapidly pushed through the die via a hydraulic system such as a press ram helps to mitigate the wall thickness dilemma. Many well-built blow molders include parison programming which allows the machine to alter the thickness of the parison as it is being formed. The combination of the above processes allows accumulator blow molding machines to efficiently produce heavy, hollow plastic products with uniform wall thickness. Examples of the types of products made on accumulator blow molders are large drums, garbage cans, and gas tanks using resins such as HDPE, PP, and PPO. Examples of the wide variety of new and used accumulator blow molders for sale that Machinery Center offers include Graham Engineering, Davis-Standard, Uniloy, Kautex, Jackson Machinery, and R&B Plastics.