The victim was operating a foot pedal saw on 21 March 2016 when his hand came into contact with the rotating blade, Birmingham Magistrates' Court was told. He sustained a severed hand a wrist.
An investigation by the Health and Safety Executive (HSE) found PES, which supplies prefabricated pipework for commercial and industrial applications, had incorrectly installed the machine in accordance with the manufacturer's instructions.
The failure meant it could be operated from a position that took the operator very close to the saw's moving blade.
PES pleaded guilty to breaching reg 17(2) of the Provision and Use of Work Equipment, under whcih employers are required to prevent work equipment operators being exposed to safety risks. It was fined £24,000 and ordered to pay costs of £2,087.
HSE principal inspector Geoffrey Brown said: "The company failed to ensure the machinery was set up in a safe manner and as a result the worker suffered life changing injuries.
"To prevent future, similar accidents it is essential that duty holders install and set up machines correctly and in accordance with the manufacturer's instructions."