MECHANICAL PRESS RETROFITTING AN OPTION WELL WORTH CONSIDERING

In the metal stamping industry, the pressure to modernise the machine fleet is constant. But replacing a mechanical press with new equipment involves considerable investment. There is a technically sound and far more cost-effective alternative: a complete retrofit.

In this article we explain what a full retrofit involves, the methodology applied to each system, and the real savings that can be achieved compared with buying new machinery.

What is mechanical press retrofitting?

The term retrofitting describes the process of modernising existing industrial equipment by replacing or upgrading its critical components, integrating current technology without replacing the main structure. In the case of a mechanical press, this is an intervention that goes well beyond ordinary preventive maintenance.

A complete retrofit covers the mechanics (crankshaft, main shaft, connecting rods, clutch, brake, guides, frame), the electronics and control (PLC, HMI, safety systems) and the hydraulics where relevant (overload protection, stroke changes). The result is, in practice, an as-new machine built on a proven, highly robust structure.

When is a full retrofit justified?

Not every old press is a candidate. Retrofitting makes sense when the main structure — frame, columns, slide guides — retains its dimensional and structural integrity. The signs that the time has come to act are:

• A sustained rise in unplanned stoppages and repair times
• Obsolete control systems with no manufacturer support
• Increased production reject rates due to out-of-tolerance parts
• Non-compliance with current machinery safety standards (EN ISO 16092)
• Noise and vibration caused by wear in the drivetrain

Stages of a full retrofit: what it involves

A complete, properly executed retrofit is not an improvised workshop job. It follows a structured, phased methodology with technical documentation at every step.

1. Initial technical audit Dimensional and structural inspection of the frame, measurement of clearances in guides and pins, and review of the maintenance history. This determines whether the project is viable and estimates the real scope before committing any budget.
2. Full stripdown and cleaning Complete disassembly down to the bare frame. Industrial cleaning of all housings, removal of worn bushes and bearings, and a final assessment of the condition of the working surfaces.
3. Frame and guide reconditioning Inspection and refinishing of the bolster on the frame and slide. Machining or scraping of the sliding guides and replacement of bronzes or gibs where necessary. In many cases original manufacturing tolerances are recovered.
4. Inspection and overhaul of the drivetrain The crankshaft and main shaft are not replaced as a matter of routine: they undergo dye penetrant testing to detect the onset of cracks that are invisible to the naked eye, caused by fatigue accumulated over millions of cycles. Replacement is carried out only if indications appear; otherwise the parts are refinished and reconditioned. All bearings, O-rings and oil seals are replaced, and the flywheel is inspected.
5. Full overhaul of clutch and brake Disassembly and thorough internal cleaning of the clutch. Replacement of collars and inspection of all internal elements: friction disc, springs, tie rods and friction linings. Replacement of fasteners, bushings and pins. Keyways are corrected to eliminate clearance; where the design allows, they are replaced with tapered locking units to remove play permanently.
6. New control system (PLC + HMI) Installation of a current PLC with a touch HMI. All working cycles, fault management and lubrication control are programmed, replacing obsolete relay logic or unsupported controllers.
7. Upgrade of safety systems Type 4 light curtains (EN 62061), a certified SIL 3 safety module, an approved two-hand control and emergency stops to EN ISO 13850. The machine leaves the workshop compliant with the Machinery Directive 2006/42/EC.
8. Testing, commissioning and documentation A full cycle of no-load and loaded tests. Measurement of the repeatability of bottom dead centre (BDC), verification of braking torque, and issue of the required documentation with an updated operator manual.

Technical benefits that are often underestimated

Dimensional repeatability restored

Eliminating clearances and deformation in the guides, in the stroke-change components and in the journal and connecting-rod bronzes restores working tolerances.

Updated safety without sacrificing productivity

Modern safety systems — safety light curtains, certified PLCs — offer greater protection without the dead time of old mechanical solutions. The result is a safer environment that also reduces involuntary stoppages caused by the accidental triggering of obsolete guarding devices.

Conclusion: the most cost-effective decision may already be on your shop floor

Before approving the budget for a new mechanical press, it is worth commissioning a technical audit of the existing equipment. In most cases, a press more than 20 years old with a sound structure can undergo a full retrofit that leaves it operating in a condition equal to or better than the original, fully compliant with current standards, at a cost of between 30 and 50% of an equivalent new machine.