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
| 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 |