Designandmake DIY craft CNC

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Re: Designandmake DIY craft CNC

Postby LittleGreyMan » Thu Apr 19, 2018 1:55 pm

TSM2018, as already mentioned, you should name materials by their chemical name to avoid confusion. Plexiglas, Altuglass, Perspex, … are acrylic or PMMA brands.

Lexan is a polycarbonate brand, which is absolutely not the same material.

The brand is not relevant, the chemical composition is.

AFAIK (but I have no practical experience for this), you can laser cut acrylic. I'm not surprised by Steven's comment. But he is mentioning a high end laser brand, probably powerful and with a good air extractor. Maybe it doesn't cut well on amateur laser or people don't want to cut it because of gaz emanations.

Have a look at this link: https://howtolaser.com/blog/how-to-laser-cut-acrylic/
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Re: Designandmake DIY craft CNC

Postby TSM2018 » Fri Aug 24, 2018 3:54 am

The STL files for this project are for printing the components that the lasered acrylic will use. I found a lot of scrap acrylic in the shop and thought oh, I should try to cut some of the acrylic on my router and see what happens, and then the light bulb turned on. If I don't use 3mm, 5 mm and 10 mm thickness of acrylic I don't think my parts are going to fit into the STL printed parts for assembly.

We can match 3 mm = 1/8", I have been able to find this, but not able as of today to get precisely to 5 mm and 10 mm, so I sent out a quote request. The cost of importing Perspex from a UK vendor seems a little high... Any one from vectric want to bring me some Perspex back to the US from the vectric meeting in Chicago? Hahaha.... no sent a quote request today to see if an actual fabricator can do the laser cutting for me with the precise thickness. Perspex is a Lucite Product, so I called and left a message with Optix as it appears they are the US Contact, to see if 5 mm and 10 mm is available.

This is pretty complicated.

And thinking through all the possible reasons after I spend $300 - $400 that it may not assemble sucessfully if the acrylic is not the proper thickness... so the 2nd thought was to buy acrylic that is thicker, and suface it down at the edge where it is too thick, then flame it if I don't like the appearance, but this also adds to the cost.

Perhaps no one has actually done this project in the US that is reading the forum?

And, I am not sure of the formula to speak in specification of acrylic; without having an expert or salesperson explain the chemical formulas of these different products and the translation of mfg from the Europe to the USA, the formula's on various websites are unclear; I am happy just seeing cast and extruded in the info online.
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Re: Designandmake DIY craft CNC

Postby TSM2018 » Fri Aug 24, 2018 8:18 pm

I'm all in, as I just mail ordered my cast acrylic. The goal is to have it assembled before the Chicago User group meeting, so I have also called the local makers space to get my parts printed, and am in the gathering of the supply stage.

I am attempting to avoid the extruded acrylic from the big box stores.

When I open the files in Aspire, I want to change the job material size because the makerspace maximum machining area is 350 mm x 400 mm or 13.7" x 15.7" in their boss laser 1416. When I printed the files via a PDF on 11" x 17" paper (fit to size) I am definitely going over the allowed space if I use the makerspace's equipment.

I also contacted a local professional plastics company to see how much they would charge me to cut the files for me, as I'm sure they are not limited to such a small laser machining area.

Thanks -
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Re: Designandmake DIY craft CNC

Postby TSM2018 » Tue Aug 28, 2018 1:10 am

CAST Acrylic arrived today, and I think I am able to open the files from previous email, so no additional help from Design and Make needed at this time. I will see how it goes; I ordered pieces 24"x32" and if I take them to the makerspace, I will just cut them on the table saw for the makerspace bed. It is miserable in the shop right now, in terms of weather; so I spent a lot of time yesterday in front of Aspire.

I am still going to try 1:1 printing, I have a 11"x17" printer, so I am hoping I can print 1:1 with the poster mode in adobe. This will allow me to see if I can cut it on my CNC router, instead. All those tiny hexagons in one of the pieces makes me hesitate, but anything that is plain, I may re-nest the parts and cut what I can on the CNC router with specialized acrylic router bits instead and the appropriate number of passes, and only laser what is necessary at the makerspace as, I'm still waiting for the local plastics fabricator to return my call and give me their quote.

The challenge is on and I look forward to see if I can create this very 'safe' project.
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Re: Designandmake DIY craft CNC

Postby 4DThinker » Tue Aug 28, 2018 8:36 pm

Is there any reason why baltic birch plywood, also available in metric thicknesses, would not be a good alternative for the plexiglass/acrylic parts?
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Re: Designandmake DIY craft CNC

Postby GerryAttrick » Tue Aug 28, 2018 9:27 pm

I am following this closely as I have a Proxxon that would be great for the same thing in lieu of the dremel.

I have downloaded the files with the idea of maybe cutting it on my Shapeoko but i am still building it and so far can't even use it :oops:

Can you tell me if the dxf files have the dimensions for the acrylic sheet(or let me know what they are) as I will have to hunt some out. I have a couple of sign writer friends who may be able to help there.

I think this subject will have a life of its own so a separate sub group or its own forum/group would be nice. Anyone else think the same?
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Re: Designandmake DIY craft CNC

Postby Leo » Wed Aug 29, 2018 12:52 am

adze_cnc wrote:
Leo wrote:DO NOT laser plexiglass - that is NOT acrylic - and is NOT laser friendly.


Fascinating, our laser cutter manufacturer sees no problem with cutting Plexiglas®: https://www.troteclaser.com/en-ca/applications/acrylic-plexiglass/


Sorry, my bad. Plexiglass IS actually acrylic and is certainly laserable.

I confused it with lexan, which is polycarbonate. This gives off fumes that are harmful to the lungs. Maybe a commercial company can cut it with laser in a controlled environment, but don't do it in a home shop.
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Re: Designandmake DIY craft CNC

Postby Leo » Wed Aug 29, 2018 1:00 am

Cast acrylic is certainly better than the stuff at the big box store, which is extruded acrylic. There is nothing wrong with the box store extruded arcylic, but with engraving the cast will produce a frosted surface whereas the extruded engraving will be more of a clear engraving.

Perpex is just a brand name for acrylic.

There are several US based vendors of cast and extruded acrylic. I have ordered from Johnson Plastics a few times.

If I have my choices between CNC router and Laser to cut either extruded or cast acrylic - I will choose the laser hands down every time.
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Re: Designandmake DIY craft CNC

Postby TSM2018 » Wed Aug 29, 2018 3:21 am

From Gerry>>

I have downloaded the files with the idea of maybe cutting it on my Shapeoko but i am still building it and so far can't even use it :oops:

Can you tell me if the dxf files have the dimensions for the acrylic sheet(or let me know what they are) as I will have to hunt some out. I have a couple of sign writer friends who may be able to help there.

Gerry, The acrylic pieces are laid out on a job size of 400x600 mm or 15.748" x 23.622" requiring,


QTY 3 each 3 mm thick pieces
QTY 5 each 5 mm thick pieces
QTY 2 each 10 mm thick pieces

The only thing I think you should consider is if the dimensions of the 3d printed parts will actually hold the proxxon dremel type tool.

After a lot of thought, I finally figured out that there is risk into changing the designs around, as the specs from the instructions and hardware are based upon the thickness of the machined parts.
There is extra space in a couple of the layouts, so I think it would have been better to have given us the file for each thickness so we could re-nest based upon the laser size of each piece.

Yes, I do think you could use birch plywood - wouldn't hurt for a prototype, and you may decide you like the way it looks better. I am using acrylic as I think it will wear better over time.

Machinists build tolerances into their jobs, correct? I don't know how much tolerance is build into the plastic 3D printed items to accept parts that are not meeting the specifications of perspex. I would love to get samples of actual perspex from the UK to put calipers on them, it would be interesting. Perhaps our friends at Vectric will bring some to the USERS Group meeting in Chicago.

Perspex in the UK, is LUCITE in the USA, I called and left a message for someone in Sales at Plaskolite, specifically, where to buy CAST acrylic in the USA, of the specified dimension, still no return phone call 3 days later. The cost to purchase the necessary sized items translated from british sterling pound to us dollar was $188.24 without shipping. Perspex' website directs me to Plaskolite in the USA. The Optix L Series is a continuous cast product.

Leo, I do agree that laser is the preferred method! Although I'm not convinced yet that I couldn't have got by with the extruded from the Lowes, Menards, Home Depot, but when I priced it out, my cost at Auburn Plastics in the Indianapolis area is CAST acrylic and less expensive even with the shipping cost. Thinking I would send the job in larger sheets to the plastics fabricator locally, I ordered sheets that were 24x32. I know Lexan polycarbonate from Menards does not work at the laser at our makerspace. I bought it because it indicated 10 yr limited warranty against yellowing, but the edges turned yellow. Boss Laser does have a guide for its users for different types of materials. I will have to find that before I go back if they laser for me. Should this turn out nicely and looks good, I am sure husband will flame edges for me. I realize the local plastics fabricator may require I purchase their sheet goods, so I've got acrylic for edge lit signs or something in the future then.

I could have missed something, but I basically studied this for about a week, not continuously, but it was the topic of last week for me... so the DIY CNC is a proving concept for me, that I can make my own CNC with instructions, without a huge price, and it may be nice to have a little desktop for 3rd generation to play with. I won't have to be crazy if they put the dremel through the bed of the machine, and doing that to the bed of the 24x40 would make me a little crazy.
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Re: Designandmake DIY craft CNC

Postby TSM2018 » Wed Aug 29, 2018 3:28 am

Leo wrote:
adze_cnc wrote:
Leo wrote:DO NOT laser plexiglass - that is NOT acrylic - and is NOT laser friendly.


Fascinating, our laser cutter manufacturer sees no problem with cutting Plexiglas®: https://www.troteclaser.com/en-ca/applications/acrylic-plexiglass/


Sorry, my bad. Plexiglass IS actually acrylic and is certainly laserable.

I confused it with lexan, which is polycarbonate. This gives off fumes that are harmful to the lungs. Maybe a commercial company can cut it with laser in a controlled environment, but don't do it in a home shop.


Yes, I do agree, LEXAN Polycarbonate that I purchased from Menards that promises 10 year limited warranty against yellowing results in ugly gold edge when lasered. I DO NOT recommend LEXAN for laser purposes. $8 experiment gone bad.
This was before I got my CNC though, so I was younger and inexperienced, now I'm just a little older and ask questions first. :shock:
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Re: Designandmake DIY craft CNC

Postby TSM2018 » Wed Aug 29, 2018 11:15 pm

FYI: The printed parts are approximately 820 grams total, and my makerspace is $0.10 per gram. This is $82.00
The 11.46 "GDP" is not MY reality without owning a 3D printer. Is this supposed to be GBP? The XE Currency convertor today converts this to $14.93.
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Re: Designandmake DIY craft CNC

Postby GerryAttrick » Thu Aug 30, 2018 11:30 pm

Thanks for those dimensions TSM2018.

I'll start with an order for the acrylic and get those cut first. I am not worried about whether to use cast acrylic or not as , other than the enclosure , there does not seem any point in being able to see through it.

I expect to have to redesign and print the mount for the Proxxon but that will be a good project for my learning CAD and also 3d printing. My only concern might be the quality of 3d printing of things like gear wheels on a "cheap" hobby grade printer. Our engineering workshop has a Makerbot so I might ask them to do the gears as they will need reasonable quality and accuracy. Unfortunately we don't have Makerspace (so far as I know) in New Zealand so I am limited to using commercial outlets for laser cutting and prices are pretty steep.

If using plywood (or acrylic) and cutting on a CNC machine you would need to consider the need to ensure square comers as opposed to the slightly rounded finish produced using end endmill.

I'll buy the bits as I can afford them and follow your project with interest.
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Re: Designandmake DIY craft CNC

Postby TSM2018 » Sun Sep 02, 2018 3:49 am

I have found a work contact and I think we both are going to make one... so I'm ordering additional acrylic. The equipment is a 600 mm x 900 mm laser bed, and my contact has great professional experience with 3D printing and the electronics, so I will start sourcing metric hardware next.

I cut and pasted the 3mm, 5mm , and 10 mm files into a larger material and that worked pretty easily. I am not able to delete the extra blank pages though in the *.crv files, so that was the only thing that I thought was strange, and I created a visual cut sheet of the qty required for each piece that will be lasered, if I am not around to feed the laser. While I have Aspire v 9.x I just cut and pasted and nudged the parts, instead of re-nesting them. That part was easy, and didn't take an hour to move everything around for a larger piece of acrylic.

I too, worried about the gears, and if I like the concept, then I may re-make the gears in metal with the my desktop CNC mill after I do the other first project with my CNC Mill.

It is never too late to start a Makerspace in NZ!
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Re: Designandmake DIY craft CNC

Postby GerryAttrick » Thu Sep 13, 2018 10:38 pm

Hmm..this could be expensive.

I just got a quote to cut the 10mm files in acrylic...$NZ265 including tax. That's not gonna happen on my watch. By the time I get all the 3mm & 5mm parts cut the price would be more than I paid for my Shapeoko3 and freighting it to NZ

I guess I have a couple of options:
1. Try to get them cut overseas and shipped- might still be too expensive.
2. Machine them on the Shapeoko3 - thats likely to be harder as I'd need to alter the existing files to allow for the use of the endmill.

I think I will put this on the back burner and watch for a while. I have just scored a 3d printer so maybe spend some time learning that and cut some of the 3d printed parts.
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