Reelyology Reel Workshop

Started by mahfudzmn, November 03, 2017, 06:11:43 AM

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jurelometer

Greetings from a fellow CNCer!!

Saw the YouTube video of the drag washer cutting.  Carbon fiber dust  is nasty stuff for electronic components.   Since it is highly conductive and gets everywhere,  it is really good at shorting out circuit boards, and even randomly turning on your equipment if it is electronically switched.  The shop I use won't allow any carbon fiber on the CNC routers or mills.

   While you do use a vacuum afterwards  (HEPA?),  have you considered a dust extractor mount for the vacuum right on the spindle?  They are easy to make, cheap to buy.     These work well when the chips are not hot enough to cause a fire (e.g.  cutting aluminum and vacuuming the hot chips up), and  can really decrease the amount of dust in the electronics, walls, ceiling, your lungs (!!!), etc.  They also really help to avoid packing/recutting once  you use the CNC to make deeper cuts for other projects.

Even better perhaps- a drag knife attachment.  These are used to cut  thinner materials including carbon fiber sheets.  You can also buy or make ones that drop right in.  Basically these are glorified xacto knifes that are spring loaded  for tension.   There are brands that use cheap standard utility knife blades that will cut a circle down to 1/16 inch radius.    A drag knife will generate next to no dust.   I haven't played around with drag knifes myself, but would definitely look into it if I were cutting carbon fiber washers.   There has to be a way to do this.  When looking at your video, the next in the related queue was somebody cutting CF washers by sharpening the points on a set of hardware store calipers...

A drag knife might not require as rigid a holdown setup as using a rotating router bit.

Just some  thoughts.

-Jurelometer

alantani

you guys are amazing.  this is all way beyond my pay grade. 
send me an email at alantani@yahoo.com for questions!

mahfudzmn

Quote from: alantani on November 05, 2017, 08:39:33 PM
you guys are amazing.  this is all way beyond my pay grade. 

It's nothing too fancy Alan, it's just the way I needed to do it to cover the reels in the market here. Custom cut is the way to go here  ;D
I've been doing it by hand, and got really tired of it. The dust it generates? Amazing when doing it by hand turning using the Dremel as a lathe. Making 20-30 washers is easily half day to three quarters of the the day spent. With the CNC I could make just about any washers, the shapes I couldn't do before. And it makes 20-30 washers in less than half an hour. That's a real bargain  :D :D





mahfudzmn

Quote from: jurelometer on November 05, 2017, 08:23:13 PM
Greetings from a fellow CNCer!!

Saw the YouTube video of the drag washer cutting.  Carbon fiber dust  is nasty stuff for electronic components.   Since it is highly conductive and gets everywhere,  it is really good at shorting out circuit boards, and even randomly turning on your equipment if it is electronically switched.  The shop I use won't allow any carbon fiber on the CNC routers or mills.

   While you do use a vacuum afterwards  (HEPA?),  have you considered a dust extractor mount for the vacuum right on the spindle?  They are easy to make, cheap to buy.     These work well when the chips are not hot enough to cause a fire (e.g.  cutting aluminum and vacuuming the hot chips up), and  can really decrease the amount of dust in the electronics, walls, ceiling, your lungs (!!!), etc.  They also really help to avoid packing/recutting once  you use the CNC to make deeper cuts for other projects.

Even better perhaps- a drag knife attachment.  These are used to cut  thinner materials including carbon fiber sheets.  You can also buy or make ones that drop right in.  Basically these are glorified xacto knifes that are spring loaded  for tension.   There are brands that use cheap standard utility knife blades that will cut a circle down to 1/16 inch radius.    A drag knife will generate next to no dust.   I haven't played around with drag knifes myself, but would definitely look into it if I were cutting carbon fiber washers.   There has to be a way to do this.  When looking at your video, the next in the related queue was somebody cutting CF washers by sharpening the points on a set of hardware store calipers...

A drag knife might not require as rigid a holdown setup as using a rotating router bit.

Just some  thoughts.

-Jurelometer

Thanks for your info buddy! The carbon sheet that I use has fiber glass inner core, they're pretty hard stuff to cut, just straight cuts with utility knives will already chip them, I don't think a knife insert would work as well as the current end mill, works fantastic

Carbon and fiber glass is no good for lungs, I now know they're no good for electronics thanks to you! I'm working on a dust boot/shoe. From what I see the dust is pretty heavy the bulk of it stays put. But it's really the 'light' ones I'm concerned about, you can't see them but they'll accumulate on the CNC parts. So here's what I came up so far...

This hose nozzle will be connected to a bucket dust collector, I hope this would be alright to capture the fine dust that tends to fly up


Ultimately, this is what I wanna build, just need to get the nylon/plastic but I just don't have the time right now. I'm new to this CNC thing and really getting raw materials to machine in Malaysia is not easy. You've got to be in the industry to find out where to buy things. Luckily I've got the help of a fellow machine shop so next I'll be able to go to the shops and source for material.

jurelometer

#19
Quote from: mahfudzmn on November 08, 2017, 07:59:44 AM
Quote from: jurelometer on November 05, 2017, 08:23:13 PM
Greetings from a fellow CNCer!!

Saw the YouTube video of the drag washer cutting.  Carbon fiber dust  is nasty stuff for electronic components.   Since it is highly conductive and gets everywhere,  it is really good at shorting out circuit boards, and even randomly turning on your equipment if it is electronically switched.  The shop I use won't allow any carbon fiber on the CNC routers or mills.

  While you do use a vacuum afterwards  (HEPA?),  have you considered a dust extractor mount for the vacuum right on the spindle?  They are easy to make, cheap to buy.     These work well when the chips are not hot enough to cause a fire (e.g.  cutting aluminum and vacuuming the hot chips up), and  can really decrease the amount of dust in the electronics, walls, ceiling, your lungs (!!!), etc.  They also really help to avoid packing/recutting once  you use the CNC to make deeper cuts for other projects.

Even better perhaps- a drag knife attachment.  These are used to cut  thinner materials including carbon fiber sheets.  You can also buy or make ones that drop right in.  Basically these are glorified xacto knifes that are spring loaded  for tension.   There are brands that use cheap standard utility knife blades that will cut a circle down to 1/16 inch radius.    A drag knife will generate next to no dust.   I haven't played around with drag knifes myself, but would definitely look into it if I were cutting carbon fiber washers.   There has to be a way to do this.  When looking at your video, the next in the related queue was somebody cutting CF washers by sharpening the points on a set of hardware store calipers...

A drag knife might not require as rigid a holdown setup as using a rotating router bit.

Just some  thoughts.

-Jurelometer

Thanks for your info buddy! The carbon sheet that I use has fiber glass inner core, they're pretty hard stuff to cut, just straight cuts with utility knives will already chip them, I don't think a knife insert would work as well as the current end mill, works fantastic

Carbon and fiber glass is no good for lungs, I now know they're no good for electronics thanks to you! I'm working on a dust boot/shoe. From what I see the dust is pretty heavy the bulk of it stays put. But it's really the 'light' ones I'm concerned about, you can't see them but they'll accumulate on the CNC parts. So here's what I came up so far...

This hose nozzle will be connected to a bucket dust collector, I hope this would be alright to capture the fine dust that tends to fly up


Ultimately, this is what I wanna build, just need to get the nylon/plastic but I just don't have the time right now. I'm new to this CNC thing and really getting raw materials to machine in Malaysia is not easy. You've got to be in the industry to find out where to buy things. Luckily I've got the help of a fellow machine shop so next I'll be able to go to the shops and source for material.


Nice!  

For a  general purpose dust boot attachment, I am partial to clear plastic with a clear vinyl skirt-  just a chunk of clear vinyl with a bunch of slits-  works really well, and more importantly,  you can see what is happening with the cut. I like the style that uses  magnets to attach the skirt holder (cut out of clear polycarbonate) to the mount (also cut out of clear polycarbonate).   This males it easy to get the skirt out of the way when mounting new bits, etc.  Acrylic would probably work ok if you use thick enough sheet stock.

Here is an example of the style: http://www.instructables.com/id/Magnetic-ShopBot-Dust-Skirt/  


For cutting drag washers, you could also make a more specialized skirt attachment with a gasket made from a length of soft round foam. When pressed  against the material, it would nearly seal the cutting area.  Since you are making very shallow cuts on flat material,  a deep skirt or brush is not necessary.

Ideally, getting the vacuum opening wider is a good idea-  the router bits tend to really shoot the dust/chips off in one direction so you need to have vacuum cover a wide area.  

And-  you can make all this using your CNC router with widely available materials!

One last trick once you have a good dust boot-  you can program up a vacuum cleaner run that covers the entire table in a series of passes with the spindle off and the vacuum on.   Once you are done cutting for the day, just run the program to help suck up the extra dust. Some CNC router software already comes with spoillboard cutting program that can be used for this,  otherwise just program up a big rectangular pocket with raster cutting path -easy.

Keep an eye on the room walls for dust building up-  that will tell you how good your dust collection is working-   Think about getting a decent mask with a particle filter.   Make a holder for the mask and safety glasses that hangs it right in front of your monitor on controller, so you can't start the machine without touching them.  

In terms or resources-   Onsrud is a maker of high quality but expensive bits-  they have good information on their website about which types of bits to use for specific materials, and more importantly chipload recommendations to help you set the speeds and feeds.   I don't use their bits frequently, but I still look up the chipload recommendations for a similar bit to get an idea of what settings to start with.    http://www.onsrud.com/xdoc/FeedSpeeds  
http://www.onsrud.com/plusdocs/Doc/list.html?pg=0&sf=code&sd=d&model.category=TECH

They have a pretty amazing range of bits for composites.    Looks like you are already getting good results already for the carbontex, but might come in handy when you decide to try some other projects.

Here is the video of the guy using sharpened calipers to cut 5mm carbontex.   I assume the 5 mm still has a phenolic core - he claims in the video to be able to cut the thicker stuff-  the edges do look a bit fuzzy.  

 I looked some more at the drag knife stuff, and it looks like they cut uncured-prepreg and not hardened sheets -oops.    If you were able to cut the thicker carbontex with the sharpened caliper technique it wouldn't be that tricky to create a nice conical spring loaded bit to do the same on the CNC- no dust! If it doesn't work, you are only out the cost of a pair of calipers...  Just an idea-  

The worst thing for me about a cnc router is the dust.   All types of fine particles are bad for your lungs over time.   If you are cutting plastics, like the resin core in the carbontex, it is important to get the speeds/feeds/ bit type right so that you are not burning the plastic- I am not an expert in this stuff either,but I have read that the toxicity problems with plastics can go way up when the materials start burning.  If the effect is cumulative, you might not figure it out that there is a problem until several years down the road when it is too late.  

-J






Keta

#20
Nice.  

The CF washers I had lazer cut had crisper edges but I am not going to buy a $500,000 + lazer cutter.
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mahfudzmn

Quote from: Keta on November 10, 2017, 02:35:21 PM
Nice.  

The CF washers I had lazer cut had crisper edges but I am not going to buy a $500,000 + lazer cutter.

That's what I thought when I first looked at laser cutters, those $500 ones won't be able to cut carbon sheets. Then I thought hey a CNC router is best plus small projects of wood, plastics and aluminum.  ;D