Knocking Noise

[Joe Pelonio]

An interesting thing happened, running a big job engraving and cutting 1/4" acrylic.

After the piece engraved I applied transfer tape to it to cut, and when I shut the lid reached down to turn on the air assist and heard a rythmic knocking sound. As you can guess, that was a little distressing. I opened the lid and it stopped. Closed the lid again and put my ear next to it, and it was really loud near the front air intake. Opened the lid again and discovered the problem. I was using 12" transfer tape on 11" material. The last inch hung loose and the air being drawn in caused it to flap violently, that's what was making the noise.

[Leigh Costello]

As I laugh, I also had a mind boggling noise occurrance. The other day, I was cutting some 1/8" Baltic Birch (Laserbuzz stuff) and kept hearing a tapping noise. I did the usual, on/off, vacuum on/off, air assist on/off. The sound was definitely related to the laser operation, but the source escaped me. Finally, I just ignored it and forgot about it. Until the next day. Same noise, but in a different spot. Sounded like it was in the exhaust tube this time. Then this morning, turned on the laser and the noise was nearer the vent to the outside. Being rather curious, I went outside and checked the vent. Apparantly, during the high winds we had on Monday, a leaf had gotten blown into the vent and down the exhaust tube. I removed the leaf, re-attached the cage to the bottom of the vent (which had come off somehow) and told myself "there are no ghosts in the laser, there are no ghosts in the laser....

[Frank Corker]

Wow, this is weird, I too had a strange noise occurence. I had a rush job which needed to go out and I was working late. The laser is in my office (used to be a bedroom and I converted it for the purpose) - anyway I was working away at 0300 and I heard this noise. I stopped the machine and checked everywhere, nothing. I started it again and the noise started, it turns out it was the wife in the adjoining room trying to get some sleep and shouting out just how she was going to go about killing me

[Bill Cunningham]

Well, if it's a continuous knocking sound, you know it ain't opportunity.. That, as they say, only knocks once..