Rack and Pinion or Ballscrews?
"Company X is trying to sell me on ball screws, claiming that anything else is inferior."
I have heard people say that many times before, at trade shows and when consulting with them about what type of CNC Router they should buy. Is there any truth to that statement? I guess that depends on what you mean by truth.
Like any machine design, a ball screw driven system is only as good as its designers. Rack and pinion allows for a lighweight design, with low rotational mass on the drive system. The typical ball screw drive system does not.
These days, many CNC Router manufacturers are employing a "rotating nut" design in the engineering of their machines. This design allows for low rotational mass. One company which uses this design is CNT Motion Systems. They use auto-lubricating ball screw design on their X axis, and helical rack-and-pinion on their Y axis. They have been making CNC Routers for a very long time, and make a fine machine. I will personally vouch for that. Why would they mix ball screws and rack-and-pinion on the same system if ball screws were so far superior to rack-and-pinion?
On October 21, 2002 Design News magazine released an article entitled "Re-evaluating the Rack-and-Pinion". This article sheds some new light on this ongoing feud between rack and pinion and ball screws. It is a very technical, in-depth article. So, for those tech-savvy readers, I encourage you to read this article. For those who are intimidated by this sort of thing, but are looking to buy a cnc router, the article basically says this: Depending on how your machine is designed, and due to the newer technologies out there, it is quite possible that rack-and-pinion beats ballscrew, both in cost, accuracy, and performance. Granted, this does not apply in every case. But you should not be duped into believing that you are better off with a slower, ball-screw driven machine, when you can buy a rack-and-pinion driven machine for the same cost and get exponentially greater speeds.
The bottom line is this: The most important thing when purchasing cnc routers is not the type of drive system it has. CNC Routers are getting to be like automobiles now:Everybody needs them, everybody makes them, everybody sells them.
The most important thing is to develop a relationship with the company that sells and supports the machine. What kind of reputation do they have? How long have they been working with CNC routers? What support medium do they use to take care of the customer after the sale? Do they have user's groups, phone support, remote assistance and support via the internet?
After all, once you've paid your 50% down, you want to know you can trust these people to take care of you, 'cause "you ain't gonna get it back." My advice is to go visit the factory of your potiential CNC router vendor in person. It may cost a few dollars, but it will ease your mind. You'll know who you are buying from, and you'll know how they operate. That way, after they have your deposit, you won't be so terrified that you made the wrong choice. You'll know you've made the right choice.
For those of you who have already bought a CNC Machine, but are having trouble getting the support you need and have exhausted your options with the factory... Or if you are in need of a retrofit for your existing control system on your older machine, email CNC Experts at info@cncexperts.com . CNC Experts can service and/or perform retrofits and upgrades on the following machines: MultiCAM, CAMaster CNC routers, WartHog CNC Routers, Digital Tool cnc routers, VyTek machines, and others.
I have heard people say that many times before, at trade shows and when consulting with them about what type of CNC Router they should buy. Is there any truth to that statement? I guess that depends on what you mean by truth.
Like any machine design, a ball screw driven system is only as good as its designers. Rack and pinion allows for a lighweight design, with low rotational mass on the drive system. The typical ball screw drive system does not.
These days, many CNC Router manufacturers are employing a "rotating nut" design in the engineering of their machines. This design allows for low rotational mass. One company which uses this design is CNT Motion Systems. They use auto-lubricating ball screw design on their X axis, and helical rack-and-pinion on their Y axis. They have been making CNC Routers for a very long time, and make a fine machine. I will personally vouch for that. Why would they mix ball screws and rack-and-pinion on the same system if ball screws were so far superior to rack-and-pinion?
On October 21, 2002 Design News magazine released an article entitled "Re-evaluating the Rack-and-Pinion". This article sheds some new light on this ongoing feud between rack and pinion and ball screws. It is a very technical, in-depth article. So, for those tech-savvy readers, I encourage you to read this article. For those who are intimidated by this sort of thing, but are looking to buy a cnc router, the article basically says this: Depending on how your machine is designed, and due to the newer technologies out there, it is quite possible that rack-and-pinion beats ballscrew, both in cost, accuracy, and performance. Granted, this does not apply in every case. But you should not be duped into believing that you are better off with a slower, ball-screw driven machine, when you can buy a rack-and-pinion driven machine for the same cost and get exponentially greater speeds.
The bottom line is this: The most important thing when purchasing cnc routers is not the type of drive system it has. CNC Routers are getting to be like automobiles now:Everybody needs them, everybody makes them, everybody sells them.
The most important thing is to develop a relationship with the company that sells and supports the machine. What kind of reputation do they have? How long have they been working with CNC routers? What support medium do they use to take care of the customer after the sale? Do they have user's groups, phone support, remote assistance and support via the internet?
After all, once you've paid your 50% down, you want to know you can trust these people to take care of you, 'cause "you ain't gonna get it back." My advice is to go visit the factory of your potiential CNC router vendor in person. It may cost a few dollars, but it will ease your mind. You'll know who you are buying from, and you'll know how they operate. That way, after they have your deposit, you won't be so terrified that you made the wrong choice. You'll know you've made the right choice.
For those of you who have already bought a CNC Machine, but are having trouble getting the support you need and have exhausted your options with the factory... Or if you are in need of a retrofit for your existing control system on your older machine, email CNC Experts at info@cncexperts.com . CNC Experts can service and/or perform retrofits and upgrades on the following machines: MultiCAM, CAMaster CNC routers, WartHog CNC Routers, Digital Tool cnc routers, VyTek machines, and others.
posted by Josh Glenn at
5/11/2006 12:56:00 PM
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