[louieatienza]

I can go on and on, but here are a few:

1 - I drilled some holes to hold some parts down with screws. After fastening the screws, I mistakenly didn't deselect the drill op in the second program. I actually milled off one screw head, but by the second one the bit was ruined.

2 - When I first started using OneCNC, I didn't know how to configure the post-processor. For some reason the park Z was at 300 (probably because it's set up in metric initially). I heard my stepper stall for a few seconds, then my Z came crashing down into the table, burning a hole in it! This had actually happened to me a few times with VCarve, where my material was very thick (I only have about 5.5" of Z travel).

3 - The ubiquitous "press start" without turning the spindle on scenario... I've conditioned myself to turn the dust collector on first, then the spindle, then Start. This will be automated eventually...

4 - The absolute/incremental I,J thing in Mach3....

5 - Ever forget to tighten that collet nut? It's not a pretty sight...

6 - Wrong parameters - Sometimes I type too fast, and don't bother to check what I type. Like cutting the full depth instead of setting a DOC, adding an extra zero to the feedrate, setting the plunge too high... all with equally disastrous results.

7 - Not cleaning the dust out of my old controller. Even Jeff at xylotex said he's only seen one other instance of a phase in an axis drive go bad. It had to be me.

8 - Impossible to weld aluminum to steel? You wouldn't think so looking at some of my bits when I first started!

9 - Sometimes I'll do some operations on one piece using two different CAM programs. Like for quickie stuff, I'll use Cut2D. For more intricate stuff I may use OneCNC. I'd forgotten a couple times to set the work origin 0,0 to center in Cut2D, with the predictable nightmare results.

10 - "Oh sure, the router should easily cut through that nail..." Nope - another ruined bit!

[Al_The_Man]

Accidentally use M4 instead of M3 and wonder why a new cutter doesn't work?
Al.

[ger21]

Try to cut at 1000 ipm and 1500 rpm, because you missed a 0.

1/2" carbide bits shatter into quite a few small pieces.

[Drools]

#5 yep.
#3 yep but the S-PID does that now.
#1 yep but because the tool path came too close to the screw I had holding the material down.
#6 yep.

Good gcode management is essential as I have ruined material by not using the revised gcode.
I have done my share of bit snapping due to stupidity. I have thought about making a check list sign and attaching it to the router.
Another big one I used to do was forgetting to set the proper bit/plate offset in the Auto Zero macro. For example when doing a PCB, I set the plate offset to 0 and let the bit touch the copper on the PCB. Well if I forget the plate is set to 0 and start a wood job then I’m air cutting which is ok but still a PITA.
The Auto Zero for X/Y is different as you can get the wrong 0,0 position if the bit/plate is set wrong, which might cause cutting into a hold-down.
Gerry said in a post, get to know the software really well, it does pay-off in the end.

[vtx1029]

Latest one was I left a razor blade on the part I was cutting and was running a drilling path sure enough it landed right on the razor blade. Spun that blade really fast. Fast enough to turn the razorblade blue and make a burn spot on the table.

[tkubic]

My favorite:
Put all clamps in place align part and start program without actually tightening any clamp. walk away to do something (never made any scary sounds) come back a minute later to see very interesting designs cut in project.

[zoeper]

Yep, i have learned (several times now) that quick is NOT fast.
"quickly" load the next job and program and hit start....without changing the tool offsets to the new jobs tools.
I hate it when i break a very nice new carbide cutter (or any cutter for that matter)

[Drools]

Also bit handling is important, carbide bits do not react well when hitting the concrete floor.

[louieatienza]

Try to cut at 1000 ipm and 1500 rpm, because you missed a 0.


1/2" carbide bits shatter into quite a few small pieces.

Nice! If you had 2 flutes that would have been a chipload of .333!

[IBBruin]

I'm glad to see the veterans making mistakes. I thought I was the only one.

[underthetire]

Pushed a turret of of square in manual. Bib boob secretary was walking by giving me the eye. I was training a new set up guy at the time. Oops.

[Walky]

1.- Ran into a screw.

2.- Reached the E-Stop box (wired) to have it at hand during a certain job, then accidentally dropped it causing an unwanted stop.

3.- Did a profiling of a small circle without bridges, causing the remaining piece to get caught between the bit and the walls, ruining the piece.

4.- Changing tools and forgetting to load the new g-code, goodbye workpiece.

5.- Ruining a lot of material trying to find the reason for inconsistent engraving width before realizing my v-bit was dull to the point of concavity.

[rnm85]

I did this on the weekend. Lent over the sign I was making to blow the dust away and the carriages ran over my t-shirt got jammed up and cut straight through my sign before I had a chance to hit the e-stop.

[cornbinder23]

Told the Z to go -1 instead of -.1 on the MDI screen the first week after I finished my conversion.
Now I have a nice .25" X .25" deep hole in the table of my mill, too bad they do what they are told
instead of what you are expecting them to do.
This little visual aid reminds me to check EVERYTHING before cycle start!

JTCUSTOMS

[vtx1029]

Told the Z to go -1 instead of -.1 on the MDI screen the first week after I finished my conversion.
Now I have a nice .25" X .25" deep hole in the table of my mill, too bad they do what they are told
instead of what you are expecting them to do.
This little visual aid reminds me to check EVERYTHING before cycle start!

JTCUSTOMS

That sticker is awesome!

[cornbinder23]

Here is a link to the sticker if anyone needs the same reminder!
They should come standard from the manufacturer!
JTCUSTOMS

[zoeper]

On my turning centre the diameter is always given in microns. If you command a G0 Y50.0 it would go to OD 50mm command a G0 Y50 and your parting tool runs through the stock to OD 50 micron!

If you have your head in your arse while programming on this one it cost you money!

[neilw20]

Wrote a program to high speed rout out a piece of chipboard held by 8mm bolts.
Calculated where bolt was and a parameter made it rout around the bolt. Spectacular at high speed with a 10mm carbide bit.
Made two. Perfect. Then did a different job on same spoil board.
Next day did a demo of it to a friend and wife.
It went straight through the bolt at high speed, un screwd the bolt with a bang, and shattered the cutter.!!!!
Reason: My 'smart program' used a parameter, that was not initialized in the start of the program. I had entered parameter by hand.
Running the different job, that used my 'favourite' parameter after my perfect two changed the value of the parameter, thereby 'moving' the bolt.

Lesson: Document ALL parameters and initalize them at the start of every program.
Only ever initialize anything in ONE place.

Bonus?? Friends wife refuses to enter workshop when visiting.

[IBBruin]

A 1/32 ball nose diamond bit in a dremel will glow red when you enter the z depth as -0.125 instead of -.0125 when etching glass.

[joshendy]

- First CNC, so excited I performed a cut in the house with MDF. TV, computer, furniture all covered with fine MDF dust. Inhaled a bunch of the MDF as well which wasn't nice.

- Old MDF CNC router I screwed up the Z depths twice on two different occasions and drove the tool through the table and then the Z axis hit its limit, continued to push until the stepper motor popped out of its mount.

- Doing two sided machining, I had secured acrylic down with 4 small nails. When I flipped the acrylic over to cut the other side I hammered the nails in same holes they had been in before. Nails didn't hold and job flung free and was wrecked.

Learning sucks but I'm getting better at doing my 'pre-cutting' checks:

- Run simulation of job, make sure it all fits within the machines limits
- Tool is secured and collet is tight
- Work piece is very tightly held down to table
- Always know how far/fast you'll need to run to hit the E-stop