G98 and G99 G-Codes are CNC programming codes used to return or cancel a canned cycle. CNC machines use canned cycles to speed up the machining process by automatically performing a series of commands that would otherwise have to be programmed manually.
G98 tells the machine to return to its original position after completing the canned cycle, while G99 cancels the canned cycle and leaves the tool in its current position.
These codes are important to know when programming CNC machining because they can help speed up the process and reduce the overall cycle time.
If you're like most people who are new to CNC machining, you probably think that all of the G-codes are used for machining operations. While it's true that most of the codes are related to machining, there are a few that are used for other purposes, like setting up the machine or formatting the program.
Two of these special codes are G98 and G99. These codes are used to tell the machine how to cut the thread.
G98 tells the machine to cut the thread in a single pass. This is the most common way to cut threads.
G99 tells the machine to cut the thread in multiple passes. This is often used when cutting very fine threads or when the thread needs to be very precise.
Knowing which G-code to use is important, because using the wrong code can result in a poorly cut thread or even damage to the machine. So, if you're not sure which code to use, be sure to ask your machinist or look it up in the manual.
In CNC machining, G98 tells the machine to start the thread at the cutting edge of the tool. This is useful for avoiding tool marks on the workpiece.
In CNC machining, G99 is a code used to tell the machine to start the thread at the bottom of the tool. This is useful for when you want to thread a hole that is already drilled, or for when you want to start the thread at a specific point on the workpiece.
G98 and G99 are both commonly used G-codes in CNC machining. They both have similar functions, but there are some key differences that should be considered when choosing which code to use.
G98 is used to return the Z-axis to the home position. It is typically used when the tool is changed or when the machine is first turned on.
G99 is used to move the Z-axis to a specific position. This position is typically set by the user based on the requirements of the job.
There are some key considerations that should be made when deciding which G-code to use. If the job requires the tool to be changed frequently, G98 may be the better choice. If the job requires precise positioning of the Z-axis, G99 may be the better choice. Ultimately, it is up to the user to decide which G-code is best for the job at hand.
G98 is the default mode when starting a new thread. It's often used when the thread doesn't need to be particularly precise, like when starting a new project or working with a new material. It's also the mode you'll use when re-starting a thread after a tool break.
G99 is acontinuous mode, which is typically used when you need to be more precise. It's often used for finishing work or for critical dimensions. Because it's a continuous mode, you'll need to be careful not to overshoot your target dimension.