Screw Barrel Manufacturer in Kolkata

Yes, we manufacture screw barrels to match the exact OEM design specifications of all major extruder brands currently in operation across Kolkata and West Bengal. For twin screw extruders, we manufacture per Kolsite, Windsor, TTS (Thayson), CMT, KMD, and Rollepal designs. For single screw extruders and injection moulding machines, we work from customer-supplied drawings, worn screw samples, or machine model references. Our machining team replicates the original flight geometry, spline or keyway profile, feed zone depth, compression ratio, and metering section dimensions precisely, ensuring direct fitment with no bore modification required on your installed machine. This is critical for Kolkata processors who cannot afford extended downtime to re-align machinery after a replacement. We also supply matched barrel sets to complement the replacement screw where the bore shows wear.

A nitrided screw barrel uses gas nitriding to harden the surface of an EN 41B – 38CrMoALA steel screw, achieving hardness of up to 68 HRC at 0.6mm case depth. This is the standard specification and provides excellent service life for processing standard PVC compounds, HDPE, PP, LDPE, and most commodity polymers. A bimetallic screw barrel applies an additional layer of wear-resistant alloy — typically 80–90% carbide-based alloy in a Cobalt or Nickel matrix achieving 68–71 HRC — over the screw flights and barrel bore using HVOF or centrifugal casting technology. Bimetallic is the preferred specification when processing high-filler PVC (25%+ calcium carbonate), glass-filled engineering plastics (30–40%), reprocessed/recycled polymers with contaminants, and rubber compounds with abrasive fillers or corrosive accelerants. For Kolkata’s PVC pipe manufacturers running high-filler UPVC and the rubber industry in Garden Reach, bimetallic is the cost-effective long-term solution despite the higher initial investment — the service life extension is typically 3–5x that of a standard nitrided barrel.

Lead times depend on the product specification and whether the order is for a standard-size barrel or a custom-geometry design. For standard single screw barrels within our regular size range (14mm to 300mm), lead times are typically 15–25 working days for nitrided specifications and 20–35 working days for bimetallic coated specifications. Custom or non-standard designs — unusual flight geometries, oversized diameters, or non-standard L/D ratios — may require 25–40 working days depending on raw material availability and machining scheduling. Logistics from Ahmedabad to Kolkata via road freight typically adds 3–5 transit days. We work with established freight partners for West Bengal delivery and can advise on the fastest routing for your requirement. For emergency breakdowns, we prioritise urgent orders and can discuss expedited production scheduling. We recommend maintaining a spare screw barrel set for critical production lines to avoid unplanned downtime.

Yes, twin screw barrels for PVC pipe extrusion — covering both parallel and conical twin screw configurations — are one of our primary product categories. We manufacture for RPVC, UPVC, and CPVC pipe specifications with the precise screw lead, root diameter taper, and inter-lobe clearance required for each polymer grade. For Kolkata’s Uluberia and Liluah-based PVC pipe plants, we supply barrel sets per the OEM machine design without requiring customers to provide full engineering drawings — we can work from machine make, model, and screw diameter reference. For plants running high-filler UPVC compounds (with 20%+ calcium carbonate as whitener and filler), we recommend bimetallic alloy coating on screw flights and HSS sleeve in the barrel — this combination delivers the best life versus cost performance in high-wear filler environments. We also supply replacement HSS sleeve inserts independently where only the sleeve shows advanced wear while the outer barrel steel remains serviceable.

Yes, we specialise in manufacturing replacement screw barrels for imported machinery where OEM spares are expensive, have long lead times, or are no longer supported. For European machines (German, Italian, Austrian extruder brands) and Japanese injection moulding machines, we work from the worn screw or barrel dimensions, OEM spare part drawings, or customer-provided specifications to reproduce the screw geometry, barrel bore configuration, and mounting interface dimensions precisely. The key advantage is cost — our replacement barrels for imported machines are typically 40–65% less expensive than OEM spare parts while meeting or exceeding the original material and hardness specifications. For Kolkata’s engineering plastics processors, cable manufacturers, and food processing plants using imported extruder equipment, this represents a significant operating cost reduction. We maintain technical documentation for a large number of imported machine models from our 25+ years of replacement barrel manufacture experience.

Our quality process embeds inspection gates at two critical junctures — before nitriding and at final inspection — ensuring every barrel that leaves our facility meets specification. Pre-nitriding inspection verifies: screw OD grinding dimensions, flight geometry and lead accuracy, spline or keyway accuracy, barrel bore diameter and cylindricity, and surface finish condition. Final inspection post-nitriding and post-grinding verifies: surface hardness (hardness tester, per-batch records), final OD and bore dimensions against drawing, surface finish Ra value, and assembly fit of ring plunger or barrel head where included. For bimetallic coated screws, coating adhesion and hardness are verified. All dispatch documentation includes the inspection record and material certification for traceability. Kolkata customers receive full documentation with each shipment. We also provide installation guidance for critical-fit components to ensure first-time correct fitment on-site.

Yes, we manufacture food-grade screw barrels in SS 304 stainless steel for food extrusion machinery. The product range includes single and twin screw barrels for pasta and vermicelli processing lines, extruded snack production machines (kurkure, puff, pellet), breakfast cereal extruders, textured soya protein lines, and general-purpose food extruder machines. SS 304 is specified for food contact applications due to its corrosion resistance, non-reactivity with food compounds, and cleanability. West Bengal’s Dankuni Food Park processors, rice and wheat-based extruded product manufacturers, and fish meal producers are the primary users of this product range. We also supply screws for double-screw food extruders and baked snacks production line machinery. Food-grade barrels are manufactured under the same multi-stage machining and quality inspection process as our standard industrial range, with material certification confirming SS 304 grade compliance.

There are clear diagnostic indicators that distinguish between a screw barrel that can be reconditioned and one that requires full replacement. Replacement is indicated when: the screw flight OD has worn beyond the re-coating threshold (typically more than 0.8mm wear on flight land diameter), bore wear has exceeded 0.5mm in diameter from nominal, or the bore shows ovality (out-of-round) greater than 0.2mm — which causes leakage across the screw-barrel clearance and uncontrolled back-mixing of melt. Reconditioning (re-chroming, re-nitriding, or bimetallic coating reapplication) is viable when: wear is within the reclaimable depth, the screw core shows no cracking or fatigue marks, and the barrel bore is within the re-honing salvage limit. Symptoms of a worn screw barrel in your Kolkata plant that warrant immediate inspection include: declining throughput at the same motor load, increased scrap rate or colour/material bleed-over, rising melt temperature at the same screw speed, excessive motor current draw, and inconsistent parison or film thickness. We offer technical consultation to Kolkata customers unsure of the replacement-versus-recondition decision.

A groove feed barrel incorporates a grooved sleeve at the feed zone of the barrel — a section of 6–8 spiral or axial grooves machined into an HSS insert that is fitted into the barrel bore at the hopper opening. The grooves create a higher friction coefficient between incoming polymer granules and the barrel wall, dramatically improving solid conveying efficiency and enabling higher mass throughput at lower back pressure. For Kolkata’s HDPE and PP processors — whether manufacturing HDPE pipes, polyolefin film, or granules — groove feed barrels typically increase throughput by 15–30% versus a plain bore barrel at the same screw speed, while simultaneously reducing melt temperature by 5–15°C due to improved conveying efficiency reducing shear heat generation. Our groove feed barrels are available in Normal Type and Spiral Type sleeve configurations. The HSS sleeve is vacuum-hardened to 60–62 HRC for wear resistance. For HDPE pipe manufacturers in Kolkata’s Howrah belt, groove feed barrel upgrade is one of the most cost-effective production efficiency improvements available — typically paying back the investment within 3–6 months of operation.

Yes, rubber extrusion screw barrels are part of our manufacturing programme. We supply both single and twin rubber extrusion screw barrels sized to customer requirements. Rubber extrusion environments place specific corrosion and wear demands on barrels — sulfur accelerants, metal oxide fillers (zinc oxide, calcium carbonate), and clay fillers in rubber compounds are all aggressive to standard nitrided steel. Our rubber extrusion barrels are manufactured with enhanced corrosion-resistant specifications — typically a bimetallic or HVOF-coated bore surface — to withstand these compound chemistries. Applications in Kolkata’s Garden Reach and Kidderpore rubber manufacturing belt include screw barrels for rubber pipe extrusion lines, rubber cable sheathing machines, rubber profile extruders, and tire component strip extruders. We can manufacture to replace imported rubber extruder barrels and can match OEM specifications where original equipment documentation is available.

Extending screw barrel service life requires attention to four operational areas: purging, temperature management, material screening, and shutdown practice. First, always purge the machine thoroughly when changing polymer grades — residue from higher-viscosity or higher-filler compounds left in the barrel accelerates wear during the subsequent run by acting as an abrasive between the screw flight and bore. Second, avoid cold starts — running an extruder at full screw speed before the barrel has reached temperature setpoint causes severe screw flight wear due to high torque on partially melted material. Third, install magnetic separators in the hopper feed to remove metal contaminants — a single steel fragment can score an HSS barrel bore surface irreparably. Fourth, follow correct shutdown sequencing — a purge with clean resin before cooling down prevents carbonised material from fusing to the screw surface and causing mechanical damage on the next startup. In Kolkata’s humid coastal climate, storage of spare screw barrel sets must include rust inhibitor treatment and dry, covered storage to prevent bore surface oxidation. Following these practices can extend service life by 20–40% versus average operating conditions.

Yes, we manufacture screw barrels for injection blow moulding machines used in pharmaceutical and cosmetic packaging production. Injection blow moulding combines an injection screw stage with a blow moulding station to produce precise-neck pharmaceutical bottles, CRC containers, and cosmetic packaging. The injection screw in these machines requires the highest dimensional precision and thermal homogeneity — any variation in shot weight directly translates to packaging weight and fill volume inconsistency, which is a regulatory compliance issue for pharmaceutical manufacturers. We supply injection blow moulding screw barrel sets with barrier screw and Maddock mixing ring designs that deliver the thermal consistency and colour distribution uniformity required for pharmaceutical-grade packaging. Kolkata’s pharmaceutical packaging manufacturers — including those supplying to the large pharmaceutical distribution hub at Kolkata port — are addressable customers for this product category.

Yes, custom screw design and manufacture is a core capability. For Kolkata processors developing proprietary polymer blends, processing speciality compounds such as WPC (wood-plastic composite), glass-filled engineering plastics, or biodegradable polymer blends, the standard general-purpose screw geometry may not deliver optimal performance. We work with customers to design screw geometries optimised for their specific compound — adjusting compression ratio, metering zone depth, feed zone pitch, and barrier flight configuration based on the polymer’s melt flow index, specific gravity, and processing window. For specialty applications, we can integrate Maddock mixing rings, barrier sections, and variable-pitch flight profiles in a single screw to solve both conveying and mixing objectives simultaneously. Custom design orders require more lead time (30–50 working days) and typically involve a technical discussion before production commencement. Kolkata customers are welcome to consult us with their compound specifications, current throughput problems, or melt quality issues — we will advise on whether a custom screw design or a standard modification is the appropriate solution.

Barrel bore wear manifests progressively — it begins with measurable diameter increase, progresses to loss of cylindricity (ovality), and in advanced stages produces visible scoring, pitting, or flaking of the nitrided or bimetallic layer. Re-honing is viable when bore wear is uniform (round and straight) and within 0.4–0.6mm oversize — a fresh HSS sleeve can be inserted to restore the specified screw-barrel clearance. Replacement is required when: bore ovality exceeds 0.3mm (indicating uneven wear, often from misalignment or abrasive damage), bore scoring depth exceeds 0.5mm (indicating metal-to-metal contact or hard contaminant damage), the nitrided case has been worn through (the grey colour of the surface changes to silver, indicating case depth depletion), or visible pitting or spalling is present — signs of corrosion fatigue in bimetallic layer or nitrided surface. For Kolkata processors running continuous multi-shift operation on PVC compounds, bore inspection every 12–18 months using a precision bore gauge is recommended to plan replacement proactively before catastrophic failure occurs. We provide bore inspection guidance and can assess worn barrel dimensions from customer-supplied measurement data.

The local Howrah engineering cluster does include some screw barrel fabricators serving the regional market. The key differentiators when comparing our supply to local fabricators come down to material specification, process capability, and quality documentation. Many local fabricators use EN 8 or EN 19 base steels (rather than MUSCO grade EN 41B – 38CrMoALA) and rely on salt-bath or atmosphere nitriding rather than controlled gas nitriding — this results in inconsistent case depth, hardness variation between batches, and shorter service life. Our process uses verified base material, calibrated gas nitriding furnaces with atmosphere control, and documented hardness testing per batch — providing traceability that local suppliers typically cannot match. On price, while our unit prices may be modestly higher than the lowest-cost local options, the total cost of ownership calculation — longer service life, fewer replacement cycles, reduced unplanned downtime — consistently makes our barrels the more economical choice for Kolkata’s larger processors. We also offer product ranges (bimetallic barrels, food-grade SS barrels, custom geometries) that most local fabricators do not have the capital equipment or technical capability to manufacture.