Acrylic on the CNC was one of the things that attracted me to the Makerspace, since they showed off the clear acrylic sign during the tour.
Hell, it might be worth installing a dedicated dust collector for the CNCā¦ but thatās a different discussion. Or notā¦ It would make it a bit easier to switch between different materials.
Iām curious: Did they mention that nothing else is currently allowed? If not, we should make sure tour guides are not giving people false information.
As I remember, they said no metal, only wood and plastics (might have said acrylic). I toured right at the end of September.
It might be a good idea to not even show the acrylic sign during the tours if plastics arenāt currently allowed on the MultiCAM.
It would also make it easier to use the MultiCAM, in general, when other tools are running in the woodshop.
Because of the wide variety of plastics, and the critical need to use the right bit at the right chipload, I think the most critical needs (after tool setup and dustcollection issues are resolved) revolve around bit setup, and from what Iāve seen, this is not widely understood among CNC users. I think Alex is on the right track with a canned tool library, but introducing plastics means moving from essentially three materials, to potentially hundreds, and so bit setup is going to require users to do a little research, and a little math, to get the rates set correctly - or theyāre going to destroy a lot of stock and a lot of expensive bits. Do we need to establish a method to check their tool values? How? Lots to consider there.
The most common tool problem I see, is running the bits too slow, in the mistaken belief that this reduces the chances of breaking a bit. In reality, it does the opposite of what the user thinks.
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While you guys are experimenting, keep in mind we have an air cooled spindle; meaning the fan that keeps it cool has a minimum RPM to be effective. If the temperature of the spindle continuously climbs and doesnāt stabilize the RPM is too low.
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Also keep in mind we still have folks that canāt cut the approved materials right yet. The more we expand and add complexity to this machine the more issues that will arise.
This is definitely an advanced move, not for people that just want to do it.
I also agree on the cleanup, its more that just picking up material off the floor, its blowing all the dust and debris from the router itself, cleaning the bits, the collets etc. I know i spend at least another full hour just on cleanup alone. If i knew how to grease/oil the bearings i would do that too.
So if you going to expand the materials list, iād limit it to folks with advanced knowledge and understanding of the machine and how it work, or folks that actually want to learn how it works.
Maint classes would be also cool
I know a basic vcarve class is needed as half the screw ups on the machine come from bad vcarve files that were just thrown together.
This isnt just one superuser using the machine its probably 50-100 mostly novice users with an idea in their head and access to a $30,000 machine. (Remember Iron Man?)
It is air-cooled, but I donāt think it has a fan. The spindle is V 50.09-2 and is listed in this catalog: http://www.crpperske.com/pdf/Perske_Catalog_25AM.pdf
Page 2 outlines the Perske spindle types
Page 6 shows the power ratings
What I havenāt quite figured out is what that āS6ā column means, other than our spindle says ā4 HP S1ā on it.
Edit: Is this (S1/S6) the duty cycle?
Edit 2: yes, it is! Magic Google wins againā¦ http://www.engineeringtoolbox.com/iec-duty-cucles-d_739.html
There is great value in the training on specific materials. I think they are particularly valuable as a starting point to high light the issues you may run into on similar materials. Personally, I want an advanced class which would include maintenance and how to setup new materials. After which you are allowed to run special materials which have a limited use, special characteristics, or you just want to build your own IP on machining them.
What kinds of screw up are you talking about here? Personally, using the Vcarve has been incredibly intuitive to me, but Iāve been working in vector and CAD for a few years now. If you send me the issues, Iāll try and develop a class that explains those issues and how to deal with them. Hopefully I can simply it down to a check list that can be added to the current training.
I disagree that any āspecial materialsā should be cut on the router. We need to make sure that all proper research is done. This machine is used by many and it needs to stay usable by all. The same rules apply to the laser. I wouldnāt expect someone to be allowed to test out new materials with out research and over sight. One persons goal is not always inline with the goal of the many. I wish there was a proper list on the wall near laser of what was allowed and what wasnāt.
There is now a team of people who will start researching how to CNC certain plastics. If you wish to CNC a certain material I think itās best to state it here so that they can research it. No need for private emails.
Stick your finger through the grill on top of the spindle and tell me it doesnāt have a fan. (No seriously, donāt do that you will lose your finger)
S1 means it can run at full RPM non stop without any loss of life to the spindle.
I agree, you probably looked at the videos and had an understanding of what you were trying to do. Most people see the CNC and are like cool, get an idea , take the class, and then they are cut loose. I know i sat in vcarve for a few weeks before i attempted using the machine. I even came in twice and my files were screwed up, luckily @Kentamanos was there to help.
Things like orientation of the material, and depth of cuts, have to be understood in vcarve. Its not just a CAD program when you start adding the toolpaths, thats where it gets sketchy. Some folks figure, hell, i drew a picture in vcarve now iām ready to go.
Bringing this up again, that huge gouge in the spoil board, goes back to somebody not having a clue about the profile depth in the software. You really cant screw up the machine once you get the setup down, that never changes, but you can screw it up with bad files. Files are created everyday and they are never the same.
Which is why i never understood why the software part is taken so lightly, after you cut that sign based on directions, everything else is a guessing game afterwards on a expensive machine.
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By chance anybody have a relationship with Professional Plastics over in Carrollton. I ordered a piece of acrylic today and the sales guy was pretty nice. Wasnāt sure if anyone hit them up on the scrap pieces, yet.
So, I have found a Plastic material that routes beautify on the router table. It is called expanded PVC. It is a plastic board that has a cellular structure and can be used with the current router feeds and speeds that we use for MDF routing. It is suggested that you use carbide tooling, but speed steel has also been shown to not have issue cutting it. When making cuts donāt use ramps, because they slow down the movement and builds up enough heat to possibly cause melting. The melting point of the material is 350* F. You can use the compression cutting end mill for cutting up to about 1/2 inch deep, after that you are going to want to use the up cut end mill for the extra chip clearing. Iāve cut inch thick with the compression end mill and it doesnāt mess up your cut edge, but it has a hard time clearing the chips of the last 1/4 inch. I havenāt had any issues with melting with the MDF cutting speeds. the chips are large and easy to vacuum up. After using the material I wouldnāt be surprised if we could cut inch thick in one pass with the up cut 1/4 inch end mill without having to slow it down. I wouldnāt suggest trying that right away, but maybe if we are striving for efficiency, we could try making deeper cuts. I have vacuumed the chips with a shop vac and the room vac system. Neither showed signs of clumping or clogging. @AlexRhodes pointed out that there may be a chance for spider web size strings to form on the collet. Iām guessing these where minor, much like saw dust gathering, as I didnāt notice them on initial inspection. But, when cutting you should check for it as other may not. As for Vcarving, it cuts nearly perfect, but I have seen the internal corner of the vcarves chip, but only in the places that were going to be cleared out with an end mill. So it might not be the right material for letters that you want to stand proud. If you have any questions feel free to ask them. For those that wonder, this is the special material Iāve been wanting to route.
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