01
Separate the iron from the electronics
Most old machines are two machines of very different ages. The mechanical part, the frame, the slides, the presses and the moulds, was built to last decades and often still holds tolerance. The electrical and control part, the PLC, the drives, the HMI and the wiring, was built with components that had a commercial life of ten to fifteen years.
When a plant says a machine is old, it usually means the electronics are old. That is the cheaper half to renew.
02
Signs a retrofit is the right call
The machine still makes good parts when it runs, but it stops too often for electrical faults. Spares for the controller or drives are hard to find. Nobody can change the program because the source is lost or the software no longer installs. Production wants cycle counts, downtime reasons or energy figures, and the machine cannot provide them.
All of these are control problems. A retrofit replaces the PLC, drives and HMI, rewires what needs it, documents everything and adds the data connection the original never had, while the machine keeps its foundation, its operators and its validated process.
03
Signs it is time to replace
Replacement makes sense when the mechanical condition is the limit: worn ways that no longer hold tolerance, a cracked frame, hydraulics that leak however often they are rebuilt, or a safety design that cannot be brought up to current expectations without rebuilding most of the guarding.
It also makes sense when the product has outgrown the machine. If the line needs twice the speed, a different material or a level of precision the mechanics cannot reach, new controls will not change the physics.
04
How to make the decision with numbers
Start with what the machine already costs you: hours of unplanned downtime last year, scrap linked to it, and the spare parts spent keeping it running. Put the retrofit price and the replacement price next to that, along with the shutdown each one needs. Replacement usually also means new foundations, new operator training and, in regulated industries, a fresh validation.
A short site survey by an engineer who looks at both the mechanical condition and the control cabinet is usually enough to make the choice clear. The answer should come from the machine, not from what the vendor sells.
Written by the ASKworX engineering team