Single screw

MAXI MELT can supply a complete range of single screws. Based on our large experience we can recommend the proper type of steel and surface treatment to minimize wear. According to customer’s needs we can propose nitriding steel, stainless steel, tool steel and in some cases also sintered steels (CPM).

We deliver screws according to OEM’s design, that match standard screw geometry. On the other hand  a plasticizing screw is the heart of the extrusion process, since upon it depends the quality of the extruded parts and also productivity in many cases. For this reason we can deliver screws with a proprietary design developed by our engineers that together with our background in polymers and polymer processing can help you in the optimisation of your production.

These screws can process all kinds of polymers and deliver better mechanical resistance, better surface finish, reduce reject rate and improve the distribution of masterbatch, improve productivity, save energy and the processing parameters become more stable and consistent in time. All these improvements are just standard for us, so that we can bind the fulfilment of these objectives to the purchase of the screw.

Up to date machinery and CAD CAM facilities make possible to manufacture also screws with complex design, barrier with maddock and mixers, over a large scale of products with tight tolerances and very fine surface finish.

Welding on screw flights

NameBase AlloyAlloy ComponentsHardness (HRC)Abrasion resistanceCorrosion resistance
Stellite 1CobaltC, Cr, W52-57xxxxxx
Stellite 12CobaltC, Cr, W44-48xxxxx
Colmonoy 57NickelC, Si, Cr, B, Fe52-56xxxxxxx
Colmonoy 83NickelTungsten carbide56-60 (x)xxxxxxxxx
CastoTIG5IronCr, V58-62xxxxxx
Suitability: (x good) to (xxxxx excellent).
(x)Tungsten carbides have a hardness of 89 HRC.

MAXI MELT offers a full range of single and twin screws. Based on our extensive experience we offer different materials types and treatments to fight wear. The materials range from nitriding steels, stainless steels, tool steels up to steels produced by powder technology (PM).

The modification of the screw geometry can improve the plasticizing process and, also, can increase its durability. The MAXI MELT screw profile offers a lower compression ratio against a standard 3 zone screw and therefore also will offer a longer life than a standard 3 zone profile.

Screw coatings

CoatingThickness of layer (mm)HardnessAbrasion resistanceCorrosion resistance
Chrome plating0,020 – 0,035800 – 1100 HV 0,1xxxxxxx
Nickel plating0,015 – 0,025500 – 600 HV 0,1xxxxxxx
PVD, TiN0,0042500 HV 0,5xxxxx
PVD, CrN0,0042100 HV 0,5xxxxxx
PVD, CrN-multi layer0,0082100 HV 0,5xxxxxxxx
Suitability: (x good) to (xxxxx excellent).

Base materials for plasticizing screws

DIN standardMaterialType steelTreatmentHardnessAbrasion resistanceCorrosion resistance
1.850941CrAlMo7Nitriding steelNitrided950 – 1100 HV5xx
1.855034CrAINi7Nitriding steelNitrided950 – 1100 HV5xx
1.2379X155CrVMo121Tool steelHardened59 – 63 HRCxxxxx
KPM1PM materialHardened58 – 63 HRCxxxxxxx
KPM2PM materialHardened55 – 60 HRCxxxxxxxx
Suitability: (x good) to (xxxxx excellent). Other materials avaiable on request. PM is powder material.