When buying a CNC rotary transfer machine, there are several things you should consider to ensure that the machine is well-suited to your specific application and manufacturing needs:

1. Size and capacity: Consider the size and capacity of the machine, including the workpiece size, the number of stations, and the type of tooling that can be used. Make sure that the machine can accommodate the parts you need to produce.
2. Precision and accuracy: Consider the precision and accuracy of the machine, including the machine’s repeatability and its ability to hold tight tolerances. Make sure that the machine meets your requirements for dimensional accuracy and surface finish.
3. Speed and productivity: Consider the speed and productivity of the machine, including the number of parts that can be produced per hour, the number of tools that can be used, and the machine’s cycle time. Make sure that the machine can meet your production requirements.
4. Automation: Consider the level of automation of the machine, including the number of pallets and the ability to perform multiple operations in a single setup. Make sure that the machine can meet your requirements for automation and flexibility.
5. Compatibility: Consider the machine’s compatibility with your existing tools, software and machines.
6. Maintenance and Service: Consider the maintenance and service of the machine, including the availability of spare parts, the cost of service, and the manufacturer’s reputation for service and support.
7. Price and budget: Consider the price of the machine and make sure it fits within your budget.
8. Future needs: Consider the future needs of your business, such as increased production volume and changes in the product line, to ensure that the machine you purchase will be able to meet those needs.

It’s important to consult with a CNC machine expert or vendor to determine which type of CNC rotary transfer machine would be best for your specific application. They can help you evaluate the specific needs of your manufacturing process and recommend the most appropriate machine to meet those needs.