Better Safe Than Sorry
Matt Roux 11.20.2013
With the purchase of a quality CNC machine tool, it’s expected that it will run and perform in the safest manner possible. There are books of regulations that specify design requirements for machine safety and these are meant to protect both the machine tool and the operator.
There are many third party items that can be added to the machine tool to improve functionality or productivity. It should also be expected that these add-ons are safe for the operator and the machine. Unfortunately there are many cases where external devices, such as automation equipment or high pressure units, are installed with the minimum of machine interface. Spare M-codes or I/O variables are used to make the add-on function. In some cases experienced personnel are able to accomplish this task. Other times things do not go well because there are concerns of inadequate safeties.
OEM Options Provide Built-in Safety
This is when I begin to think people are exposing themselves to too much trouble when they don’t review and order OEM options specific to the task. As a CNC machine builder, safety is designed into all aspects of our options. There are checks for many conditions that allow for a safe environment for the operator and safe operation of the machine and external devices. These include:
- Door open
- Workholding unclamped
- Turrets indexing
- Limit conditions
- Command signals requiring answer back
The Importance of the Right Interface
Automation items such as robots, barfeeders, and part unloaders all require two-way communication between the device and the CNC machine. A properly designed interface accounts for the multitude of functions possible that is consistent from machine to machine. There are over 30 signals in a standard robot interface, with the same set available to each machine. Not all the signals are needed all the time, but use just what is needed for the specific setup. Having and using the right signals, in my experience, makes the setup of machines a whole lot easier, and in some cases, more flexible.
In recent years there’s been increased legislation both in the U.S. and other countries for CNC machine safety. Now is a good time to start asking what interface is available for your specific needs that will keep your machines operating effectively and your operators safe.
What are you doing to ensure safety in your shop? If you think you may have a ways to go, feel free to contact us or your local distributor and we can talk about some suggestions.
Matt Roux is Applications Engineer, Okuma America Corporation.