Many machines manufactured today have a rack and pinion in the drive system.Whether these products are straight or helical, they are very important because of their positioning task.These drive systems are preferred in wood router, metal machining center or laser cutting machines, especially in the X-Y axis.
When it comes to positioning accuracy, the manufacturing quality of the pinion and rack is the first consideration.There are quality classes indicated with the letter “Q” in pinion and rack manufacturing. The number next to this letter indicates the quality of the product according to the stages it goes through while manufacturing. The quality of the manufactured products reveals a value known as the “Cumulative Pitch Error” value.
Please see the “Cumulative Pitch Error” example diagram specified by manufacturing qualities which for module 4.
Generally Q5 and Q6 quality racks and pinions are hardened and ground, while quality Q7 is milled out of alloyed tempered steel.Mostly , quality grade Q9 are milled and hardened but some manufacturers prefer to let it soft ( means not hardened) .
As a result, if a high-end machine is to be built, Q5 and Q6 should be preferred (For applications requiring high positioning accuracy. Example: Laser Cutting Machine) If a machine such as a wood router is to be manufactured, Q7 can be preferred. Q9 can also be used in applications that do not require precision, that only move a load from one location to another.