How to solve uneven flow speed in extrusion die? Here is the Answer!

Every company has its own core value. For GMA, R&D of extrusion die manifold, high precision machining process, exclusive die head maintenance procedure and complete technical support and service are all our core value. The most precious is the customer satisfaction.

In between mutual discussion with our customers, one of most concern of production issue is uneven flow distribution of extrusion die. And this issue is main reason of flow mark and thickness variation problem and shows big defect on the product surface. To improve it, the optimum flow geometry design of extrusion die is the solution to save a lot of loss of polymer and manpower during production tuning.

When the flow speed problem shows up, it is very likely that the formula or raw materials has been modified that existing designed geometry is no longer workable by adjusting lip opening only. It has to work with geometry modification of extrusion die, according to optimum simulation analysis base on each own polymer property.   Each resin has its own unique rheological properties. Different materials or different production conditions will cause shear rate variation inside flow channel that affect flow speed at each zone. This is flow speed problem.

One of GMA real case that customer feedback that they have to constantly adjust the lip opening screw of extrusion die trying to get uniform thickness when manufacturing PVA film; however still there is uneven flow speed showing up on film uniformity. In order to sort out the problem factor, we send customer’s material to lab and get the rheology data. Input the data value into flow geometry via CAE analysis software and come out with similar flow speed distribution as real status which has faster flow speed at both side of extrusion die.

(Uniformity 98%-102% faster speed at both end)

(Uniformity 99.5%-100.5% improved speed at both end)


Based on 30 years of professional experience and scientific verification, GMA provides customers optimum solution. Save trial and error test time and cost. Increase efficiency and profitability.

Via extrusion die CAE simulation, we also can find out too high back pressure and shear stress inside existing flow channel when we input customer’s material property.  After continuous communication with customers and verification tests under different conditions, an optimized geometry design of extrusion die was finally complete. Customers are all satisfied with our cooperation and scientific analysis.

In the past, production tuning was relied on experienced masters by trial-and-error method and use one extrusion die to run all kind of polymers. But low efficiency adjustment and polymer waste cost more than the price of a good suitable extrusion die.

In recent years, GMA has continuously proven and promote specific extrusion die for each resin is the best solution to maintain high production quality and stability and also makes maintenance easier.  Especially with diverse resin in the market now, to work with experienced extrusion die manufacture and CAE simulation technology, we can provide the best and the fast solution. And feedback with the customer satisfaction is the most precious of our 30 years of experience.