CanisLupus wrote: As you can image, both claim their design is the best. Both claim their approach is used on high-end machines and that demonstrates the superiority of their design.
Talk about obfuscation! WOW!
"high end" has nothing to do with it. An example is in order (all from the same company, Mitsubishi):
Their EDM machines are extremely accurate and use ball screws BECAUSE they do not have a 'need for speed' on those machines.
Their laser cutters are rack and pinion. They are also very accurate. IIRC their positioning accuracy is less than .002 inches over 10 feet of travel.
I just betchya their sales folks do not bloviate about one being superior over the other.
Accuracy has zippity doo dah to do with the type of motion system used, ball screw or rack and pinion. It has to do with things like "open loop" vs "closed loop". If a machine is running a closed loop system the motor is not controlling the positioning of the machine, either an encoder or a flat scale is doing that job. When it comes to open loop systems then things change. If a high accuracy ball screw is used then higher accuracy is obtained. But speed suffers unless big honking motors are used to drive the ball screw. A rack and pinion open loop system can be very accurate depending on the gear ratios used and the precision of the rack and pinion.
A lot of this stuff is just talking points for sales folks that is used on the unwary. The bottom line is this: What will they guarantee the positioning accuracy of the machine?
Anyone selling machines in the price ranges of these two companies trying to ride on the coat tails of the big boys by stating they use the same technology is just plain employing sales tactics.
If a sales person said that to me I would reply "Oh, so you are running a closed system on your machine then?"
Simply put, statements like that are similar to a Chevy salesperson saying "We use the same method as Rolls Royce in our cars, an engine, transmission, drive train, wheels, etc".