After executing the G80, the machine returns to G00 mode. That means you can just real off a bunch of XY coordinates once the cycle is initiated, and the machine will happily execute the cycle at each location. Multiple Holes Until G80 Cancels the CycleĪs mentioned, these drilling cycles are modal. The option to retract to the original Z height using G98 is provided in case there are obstacles between the holes such as clamps or other features of the part. If G99 is in effect, retraction is to the R height. If G98 is in effect (specified before the cycle such as the G99 shown above), retraction is back to the initial Z height. G98 and G99 g-codes are used to modify the retraction behavior of canned drilling cycles. Modifying Retract With G98 and G99 G-Codes Now retract can work in one of two ways, and is modified using G98 and G99. Remember to do that math carefully, as R will always be a little above material top and you have to add it to the actual hole depth to get your Z. So, with an R of 0.2″, and a depth (Z) of 0.7″, we are going down to Z = -0.5″. In other words, Z specifies the depth, not a particular coordinate. – Next we feed down an amount equal to Z. R is 0.2″, so we rapid from 1.0″ down to 0.2″. – Second, the tool rapids straight down to the R position, established by the “R” word of the cycle. For our example, those coordinates are X10Y12. – First, the machine rapids to the X and Y coordinates of the hole, or the corresponding pair of coordinates if a plane other than G17 is selected. It just goes down at the feedrate, and then retracts. G81 does no pecking and has no special operation at the bottom of the hole. There are a lot of parameters and options associated with the drilling cycles, so let’s start with a relatively simple one: G81. Since there are quite a few different types of canned drilling cycles, it’s easiest to classify them in tabular form:
![estlcam g04 estlcam g04](https://i.ytimg.com/vi/L4FbT0XRrPE/maxresdefault.jpg)
Different Types of Canned Drilling Cycles and Their Uses
![estlcam g04 estlcam g04](https://i.ytimg.com/vi/4K5sni7DZlM/hqdefault.jpg)
G-Wizard Calculator will remind you if you forget. Most tooling manufacturers will suggest you start when the hole is 4 diameters deep. There are some rules of thumb about when you need to start using a Peck Drilling Cycle as opposed to just plunging straight down. It increases the tendency of chipping the brittle carbide. For that reason, the best peck drill cycles will not pull the twist drill completely clear of the hole.Īnother thing to keep in mind is most manufacturers do not recommend peck drilling for carbide drills. One thing it that is important to avoid when peck drilling is letting the coolant or air/mist blast wash chips back down the hole. Second, if the twist drill retracts a substantial distance, this helps reduce the distance the helix of the twist drill has to carry chips. Shorter chips are much easier to evacuate. Peck drilling also helps with chip evacuation in two ways.įirst, even a very short peck where the retraction is minimal helps to break off the chip resulting in shorter chips. There’s only enough room down in the bore for the chips that fit in the flutes of the twist drill, and the deeper the hole, the harder it is to evacuate those chips out of the hole. The other purpose of peck drilling is improved chip evacuation. Recutting chips is always a bad thing for tool life. The reason it’s done is to evacuate the chips from the bore. Think of the motion as being not unlike a woodpecker. This is the practice of drilling a little ways (the peck distance), back off some distance, and then going back down to the bottom to take another peck. What is a “Peck Drilling Cycle”?Ī term you’ll hear a lot is “peck drilling”. For example, once we select the high speed peck drilling cycle with G73, subsequent coordinates on later lines specify new hole locations where more peck drilling will be done. In this chapter, we introduce the notion of “Canned Cycles”, which allow more complex types of motion aimed at simplifying the programming of certain common operations such as drilling holes.Ĭanned cycles are often modal just like the other motions.
![estlcam g04 estlcam g04](https://i.ytimg.com/an/y30qVPfTJ-owuswy6YwdsQ/featured_channel.jpg)
Until this point, all our motion has been done with G00/G01 for lines and G02/03 for arcs. G81, G73, G83: Drill Peck Canned Cycles CNCCookbook’s G-Code Tutorial What are Canned Cycles?