¿Cómo se verifica la precisión y la calidad de los orificios perforados y roscados en una máquina CNC?

You don’t use a drill bit ‘slightly smaller’ than the tap diameter, you minus the pitch of the thread from the tap diameter to find the drilling size, I.e. m4 thread is 0.7 pitch so it would be drilled 3.3mm, maybe 3.4mm in ‘sticky’ materials such as 7075 aluminium or stainless.

Understand the drill and tap chart, make use of calibrated measuring tools ( No go and go gauges to measure threaded diameters) check that your drills aren’t blunted and sharpened to the required angles.

For starters...choosing the right size Center drill for the right Drill that leads to the correct Tap is very important. Then depends on the measurement of the major and minor diameter after tapped hole. Im a tight tolerance type of guy .0001🦾⚙️💙

I find that it comes down to thread engagement. Unless it's a fluid or pressure fit I tend to go with 50% thread engagement leading to more holes tap before breakage. At 75% engagement alot of taps break especially in long holes or cross holes. So it you can use 50% thread engagement do it. If not make sure to get chips out effectively or snap.

The Class of the thread specified on the engineering print and the material spec will determine the drill size for standard taps. The tap holder for CNC is special and should have radial float to follow the drilled hole position. I have seen a "Thriller", combo drill and threading tool used successfully in the correct applications saving a lot of money and time. Thread milling is a different story. The metal working fluid, or special tapping compound will make a difference as well. Go/NoGo Gages must match the thread specification also.

You should pretty much never use a centre drill, most high quality drills are self centering below about 8XD. For longer drills you should use a pilot and not a centre, the pilot drill should have a point angle equal to or greater than that of the drill and should be equal diameter or ideally 0.02 - 0.03 mm larger diameter. Lots of good drills do not require peck cycles, you should avoid pecking if at all possible as the majority of the damage or wear on a drill is caused at entry so if you’re pecking then you have multiple entries and therefore more damage. Only peck in difficult to chip materials or highly abrasive materials where you can’t ensure sufficient cooling at the cutting edge

The spot drill should have a tip angle equal or greater than the following drill. This protects the web of the drill and keeps the position accurate

Some drills work best without a center or spot drill, and pecking may not be recommended by the manufacturer. Look at the tool manufacturer recomendations for the specific tool and material you are using.

Check the size of the tap we want to tap and then select the Drill bit attached to it. Subtract the tap's drill size from the tap's pitch and we get the drill size. Example M3x.5 = Tap pitch0.5 Drill size 2.5, Drill. In case of blind hole it is better to use spiral tap. Cut Tap is best if it is through hole. After drilling, check the major and minor pin. Example: M3 minor pin 2.45 major pin 2.6 If the pin enters between this, the hole is perfect. After that tap. After that check Go thread gauge and nogo thread guage and Major and minor pin.

This is a good example of why it's too early to be jumping on the "AI" bandwagon. It makes it even more likely that you simply can not trust everything (sometimes ANYTHING) you read. G84 code is not for thread milling! It is a tapping cycle. It moves the tool in and out of the material along the axis of the spindle. Thread milling requires a helical toolpath, not available with a single "G code".

To verify that you have a good tapped hole you measure. The better your measuring equipment and the more thorough your process the better chance you have to get it right. The first place I start is in the Machinery’s Handbook. It’s important to know what your tolerances are for the class of thread you’re cutting. For external threads, I prefer using a thread mic to verify pitch diameters, but thread go/no go gages are really the best option. For internal threads, I use pin gages to verify my minor diameter and thread go/no go gages to verify I’m in specification. Use CMM type machines to verify positions, if you don’t have that then break out the gage pins, granite plates, and trusty height gages! Rabbit hole fallen down!Cheers!