Single screwMAXI 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

Name Base Alloy Alloy Components Hardness (HRC) Abrasion resistance Corrosion resistance
Stellite 1 Cobalt C, Cr, W 52-57 xxx xxx
Stellite 12 Cobalt C, Cr, W 44-48 xx xxx
Colmonoy 57 Nickel C, Si, Cr, B, Fe 52-56 xxx xxxx
Colmonoy 83 Nickel Tungsten carbide 56-60 (x) xxxxx xxxx
CastoTIG5 Iron Cr, V 58-62 xxxx xx
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

Coating Thickness of layer (mm) Hardness Abrasion resistance Corrosion resistance
Chrome plating 0,020 – 0,035 800 – 1100 HV 0,1 xxxx xxx
Nickel plating 0,015 – 0,025 500 – 600 HV 0,1 xx xxxxx
PVD, TiN 0,004 2500 HV 0,5 xxx xx
PVD, CrN 0,004 2100 HV 0,5 xxx xxx
PVD, CrN-multi layer 0,008 2100 HV 0,5 xxxx xxxx
Suitability: (x good) to (xxxxx excellent).

Base materials for plasticizing screws

DIN standard Material Type steel Treatment Hardness Abrasion resistance Corrosion resistance
1.8509 41CrAlMo7 Nitriding steel Nitrided 950 – 1100 HV5 x x
1.8550 34CrAINi7 Nitriding steel Nitrided 950 – 1100 HV5 x x
1.2379 X155CrVMo121 Tool steel Hardened 59 – 63 HRC xxx xx
KPM1 PM material Hardened 58 – 63 HRC xxxx xxx
KPM2 PM material Hardened 55 – 60 HRC xxx xxxxx
Suitability: (x good) to (xxxxx excellent). Other materials avaiable on request. PM is powder material.