Plastic CNC Machining Welcome to the home of Plastic CNC Machining. Click on any of the link below to see our capabilities. Peruse the website - http://www.sentinelplastics.co.uk - for more information about us. See the many Engineering Industrial Plastics available for machining and fabrication at Sentinel Plastics Ltd Sentinel is where industry turns to for its CNC Machined Plastic Parts.