Common Problems of HDPE Plastic Extrusion Line


Ningbo Fangli Technology Co., Ltd. is a mechanical equipment manufacturer with nearly 30 years’ experiences of plastic pipe extrusion equipment, new environmental protection and new materials equipment. Since its establishment Fangli has been developed based on user’s demands. Through continuous improvement, independent R&D on the core technology and digestion & absorption of advanced technology and other means, we have developed PVC pipe extrusion line, PP-R pipe extrusion line, PE water supply / gas pipe extrusion line, which was recommended by the Chinese Ministry of Construction to replace imported products. We have gained the title of “First-class Brand in Zhejiang Province”.

To optimize productivity and operational cost, HDPE pipe extrusion line manufacturers ensure that all parameters are identified, monitored, and controlled. 

Some of the variables are hinged on the equipment and the prevailing operating conditions and this affects HDPE pipe production line cost.

These variables range from the quality of materials and die used to physical conditions such as temperatures and pressures.

Common problems associated with HDPE extrusion pipe productions are put into a few categories.

However, before you get to know these problems, partnering with a reliable HDPE pipe extrusion line manufacturer guarantees you the best quality HDPE pipe extrusion.

Common problems relating to the manufacture of HDPE extrusion pipes are put into the following categories:

1. Aesthetic Flaws

These are sink marks, tiny holes, drag marks, pits, black specs, and die lines that are found in the HDPE extrusion pipe product.

2. Variation in size

Size variance is another common problem associated with HDPE extrusion pipe products. These can be intermittent or contiguous variance in size.

3. Dimensional variation

These are irregularities in the length and width of the extrusion pipes. In preventing these problems in the extrusion processing line, the first call is to checkup the components of the manufacturing process beginning with the equipment.

The cause could be from the screw design, irregularities in the process temperature, or improperly laid die itself.

Other variables to be examined when the extruded products don’t meet the required finished product standards are:

· Melt pressure

· The velocity of the line

· The motor load

· Cooling power

· Heating power


Again, some preventative steps can be taken before the start of the production process. These are:

1.  There should be proper calibrations of instruments used to monitor changes in pressure, temperature, and amperage at least twice in a year.

This is important to ensure the readings are precise and do not drift in the course of the production.

2. A steady condition of resins should be consistently maintained.

The resins should be stored in a dry and clean place without being subjected to abrupt variations in temperature.

If the resin is too dry, it may not melt properly and hence the resin cannot be processed.

Some HDPE pipe extrusion line manufacturers carry out routine resin analysis to evaluate its quality such as melting index, shear rate, tensile strength, etc.

Changes from one batch of resin mid-way in the production process can alter the product. This should be avoided.

The machine should be monitored closely to maintain an efficient extrusion process and get rid of any quality issues.


In any HDPE manufacturing firm, the goal is to have a productive and competitive advantage over others.

Problems in the production process can hamper the realization of this dream.

Hence, the need to partner with a reliable HDPE pipe extrusion line manufacturers for professional advice and first-grade quality products.

If you need more information, Ningbo Fangli Technology Co., Ltd. welcomes you to contact for a detailed inquiry, we will provide you with professional technical guidance or equipment procurement suggestions.

  • QR