I was recently cutting shapes from 3/8" bamboo 11"x14" cutting boards using a 2-flute 1/8" Bosch bit at 23000 RPM at a feed rate of 15 inches per minute and step down of .15". The bit must have become dull and the $7 bamboo cutting board may have been oiled. Either way, I had a genuine fire at a thin part of the design that required a fire extinguisher to put out.
Wow, this was scary as hell. I am glad I was in the room and nothing was damaged except the piece because it only took me seconds to put out the flames. I realize that I may have done some dumb things and I am sure the community will steer me straight, but even so, I would recommend to every Maslow owner that you keep a good fire extinguisher near by and never leave the Maslow unattended for a lights-out operation. I keep several in my shop always in arms reach and I know I wonāt ever leave it alone like I have in the past.
Welcome to our group & that is awful there was a āCarbon Conditionā. Iām glad you were diligent in monitoring your work. Gosh I can tell you I eended up in a gas station when my car caught on fire. It was a 69 bug and the fuel line ruptured. When I asked where the fire extinguisher was they told me they didnāt have one. As I was going back in for water a guy came out trying to read the side if the extinguisher and struggling with the lever. I yelled give it to me, I had just done a class, he hadnāt pulled the pin.
Long story sort itās always good to be prepared and now all my cars have an Extinguishers.
All machines have a function and no ability to think for you. caveat emptor!
I find my Maslow to be a worthy investment but it requires my participation. Iāve seen the chain ball up in 3 seconds flat trying to feed out. Like any skill it takes time, patients and diligence.
Thank you so much for calling this to our attention. I have been so focused on the zillion details of trying to get this thing working, that the idea of a fire extinguisher nearby hadnāt occurred to meā¦ I will get one tomorrow.
Hello! Iāve got my admin hat on this morning and I wanted to let everyone know: I changed the title of this topic from āā¦My Maslow Caught Fireā to āI Started a Fire With My Maslowā
When I saw the original title I immediately pictured a flaming Arduino but the topic clearly is not that! If only to assuage a panic, I thought a title change was appropriate.
@orzot no offense was intended and I hope you donāt take offense to this change.
This is an excellent reminder of how important shop safety is and that you should never run any power tool unattended.
Thanks for sharing. Just last week I paused a long cutting process to attend an after school play my daughter was in. I was giving some thought in how to use the G code turn off spindle command to shut off the router if I left future projects running unattended. After reading your post, I think Iām going to scrap that idea.
When drilling holes if dwell time is long with compression bit, the saw dust does not leave. So it accumulates in the flutes and rubs against the wood. The friction can start a fire.
Better not drill with compression bit.
What I mean, you can drill, sink with a compression bit, but up-cut has better saw dust/chips clearing when drilling.
The issue of burning or creating a fire with a CNC is not limited to any particular machine. This can happen a basic CNC up to an industrial CNC.
Typically the reason for the fire is friction has caused the tool and material to heat hot enough to the material to burn. The question is why is the tool getting that hot? As other mentioned above the general cause is feed rate and rpm of the spindle. Too slow of a feed with high rpm creates friction resulting in the bit to get hot enough to burn the material.
Dwell time can also be an issue. If the bit plunges and pauses prior to moving or is used for drilling this will cause the bit to heat up quickly. General rule is to keep a router bit moving in the cut. If the bit is used for drilling, try using a pecking motion, where the bit goes into the material and retracts and the processed is repeated until the hole is drilled.
There are optimal feed rates and rpm for every type of bit. Yes this will involve math, yet today most manufacturers will give you a starting point.
An easy way to tell if feed rates and rpm are to slow is to check the tool. If run at a proper speed the tool should be clean and show little discoloration when the cuts are complete. Even a bit which has run its tool life should not be very discolored. The discoloration comes from the bit overheating and thus and issue with feed rates and rpm.
Dwell time can also be an issue. If the bit plunges and pauses prior to moving or is used for drilling this will cause the bit to heat up quickly. General rule is to keep a router bit moving in the cut. If the bit is used for drilling, try using a pecking motion, where the bit goes into the material and retracts and the processed is repeated until the hole is drilled.
I know this is an old post, but, what is the max travel speed for the Maslow? I would think 30 IPM (inch per minute) would be acceptable if you kept your RPM to a minimum. As an example, for a .250 inch bit (just as a guess) I would run at between 20 and 30 IPM at around 15000 RPM with a depth of cut of .100. I base these numbers off my CNC Mill (Hurco and HAAS) experience. Let me know if you guys think Iām close or if Iām way off. As a rule of thumb, at least for metal cutting machines, if it sounds good when cutting then its probably good.
