The first choice is the abrasive delivery method – either siphon or direct pressure delivery. Will the primary use call for surface etching or blending large open areas? If so, then the siphon machine is ideal. If a more focused pattern or deeper carving is required, then a direct pressure machine is preferred. Direct pressure also allows processing with lower blasting pressure using less compressed air and enabling more mask detail.
The next question in selecting the right sandcarving cabinet concerns the required volume or flow of abrasive through the nozzle. The size of the nozzle determines the volume or flow of abrasive. The industry refers to small nozzles as micro and large nozzles as macro. In direct pressure, micro nozzles are 1/8-inch I.D. or smaller and macro nozzles are 3/16 or larger. In siphon delivery cabinets, micro nozzles are 1/4-inch I.D. or smaller and macro nozzles are 5/16 or larger. The greater the flow of abrasive, the higher the frictional heat, and the higher the frictional heat, the less design detail. Micro nozzles with less frictional heat are used for detailed design work – whether in high production runs or one-time-only part production.
After deciding the abrasive delivery method (siphon or direct pressure) and volume or flow of abrasive (micro or macro) the buyer will next need to consider the machine duty cycle.
Machine duty cycle is the amount of time the machine is designed to operate on a daily basis. Duty cycle is determined by the size of the exhaust blower and the size of the dust collector filter. The right machine cycle will match the highest anticipated daily usage.
—Media Blast & Abrasive Inc.
