makernexuswiki - User contributions [en]

MN Metal Shop

2022-12-17T18:08:08Z

JeffG: /* CNC Tools */

<div style="
border: 1px solid black;
padding: 2px 6px 2px 6px;
background-color:pink">Note: We have one manual lathe and a mill available for member use. Our sheet metal area is also available. Volunteers are working to bring the CNC metal tools into usable condition.</div>

== Lathes ==
* [[Clausing-Colchester 6527 13" x 36" Gap Bed Lathe]]
* [[LeBlond Regal 13" x 42" Lathe]]

== Milling Machines ==
* Bridgeport J-Head Mill
* Bridgeport J-Head Variable Speed Mill
* [[Kearney & Trecker 2H 10" x 50" Horizontal Milling Machine]]

== CNC Tools ==
* CNC Hitachi-Seiki Lathe
* Matsuura MC-500V Vertical Machining Center CNC Mill
* Cincinnati Sinker EDM
* Birmingham CNC Conversion Mill

== Welding ==
[[Welding tips]]
* MIG Welding
** Millermatic
** Lincoln Electric
** Harbor Freight
* TIG Welding
** Lincoln Electric TIG Welder
* Arc Welding

== Drill Press ==
* Delta Drill Press

== Saws ==

* Horizontal Band Saw
* Vertical Band Saw
* [[Makita LC1230 12" Metal Cutting Saw]]

== Grinders ==
* [[K. O. Lee S718 6" x 19" Surface Grinder]]
* Pedestal Grinder

== Buffing Arbor ==

== Sheet Metal Tools ==

* Finger Brake
* Foot Shear
* [[Roper Whitney No. 58 5-Ton Punch Press]]

== Handheld Power Tools ==

== Hand Tools ==

Back to [[Maker_Nexus_Equipment]]

[[Category:Equipment]]

Vacuum Forming

2022-12-17T17:42:09Z

JeffG:

= Techniques =

== Prevent undersuck ==

If your model has any space under it, the plastic will form under the model and make it impossible to release. One way to prevent this is to place your model on a bit of wood and use modeling clay to block the bottom edge of the model.

I have tried both water based, air drying clay (the kind you might use to make a pot) and an oil based, never hardens modeling clay.

The never harden clay melted just a bit with the vacuum forming heat and was a mess to clean up. I placed the clay more as a "rope" around the model and that left a lot of nooks and crannies in the formed plastic that clay was stuck in. On one cycle, for some reason, I smoothed out the clay with my finger and that made the clean up much easier. Still, it is a pain and I don't recommend it.

The water based clay seems like it's going to dry on everything and be a mess. In fact it is easier to clean up. The clay did not "melt a bit" in the heat of forming; I think it became a bit harder. Then the clean up is easy with just flooding the formed plastic with water. I wish I had never thought to try the oil based clay!

= Materials =

== PET-G (Vivak) ==
This material is said to be food safe. I had the vacuum former set for 3 and this sheet was ready in 40 seconds.
*0.04 inch... I bought a 24x48 inch sheet of 0.04 inch material from [http://usplastic.com http://usplastic.com] for $18 plus $10 shipping. Out of that I cut two 20x20 sheets. So the cost was $15 per sheet.
*0.02 inch... Bought a precut 24x24 sheet from amazon. $5 for the sheet, $6 for shipping. Total of $11 per sheet.

== Styrene ==
1/32 inch material: It formed easily and with very good detail.  I set the heaters to 3 and the plastic was ready in about 30 seconds.
*Tap Plastics. They charge $2.15 per square foot; sheet cost $6.00.

0.03 inch material: I set the vacuum former heaters on 3. This material took 50 seconds to be ready to form. It formed very nicely with excellent detail. I found that this is substantially thinner material than the 1/32 inch sheets from Tap Plastic.<br/>I wish I had ordered 0.04 inch material from US Plastics.

*US Plastics. I bought a 40x72 inch sheet of 0.03 inch styrene from [http://usplastic.com http://usplastic.com] (item 043331) It cost $10 and shipping was another $10. It came in a rolled up tube. I cut it into 6 20x20 inch sheets on the power shear. The cost per sheet was $3.25
0.04 inch material: tell us about your experience
= Supplies =

== Mold Release ==

For styrene and PETG I used CRC Food Grade Silicone Mold Release. I think it really helped the plaster form to come loose. I recommend it. I bought my can at Amazon; it was inexpensive.

If creating a MDF Mold, Sand it first. Then you can use Johnston's paste wax to coat the mold. Let dry and buff out, do multiple coats.

ShopBot tips

2022-12-17T17:39:42Z

JeffG:

Q: What is the max feed rate of the ShopBot?

:A: Depends on bit, pass depth and material. 1.5 IPS (90 IPM) is a good starting point for most use cases. If you are cutting very soft foam you could go much faster but anything over ~250 IPM would lose steps.

:If your material is thinner than 0.25 inches you might consider using a spiral down bit.

Q: The Shopbot "Feeds and Speeds" doc talks about "soft plywood" and "laminated plywood". But isn't all plywood laminated by definition?

:A: They mean veneered ply, different feeds will leave cleaner cuts.

Q: The Feeds and Speed doc doesn't list any settings for '1/4” Downcut Carbide End Mill'

:A: The doc is far from comprehensive. The ideal tool is a 3/8" compression for small projects but the 1/4” Downcut Carbide End Mill is 90% as good for less than half the cost.

Q: What is a reasonable chip load?

:A: For a quarter inch bit I generally run a chip load around .010 inch per tooth.

Q: I have a 1/8 inch bit but the collet is larger than that.

:A: Put the bit in and squeeze the collet in one hand. Try yo lightly pull the bit out of the collet, if the bit is in snug, then you can use that collet. Many collets have a range of about 1mm, or 0.04“

Q: How do I run an air pass on the MN ShopBot?

:A: If you use the special MakerNexus post processor it’s pretty hard to do an air pass. Two strategies come to mind, both requiring a second output of your shopbot code. First, lie to VCarve about the thickness of your material by an inch or two, (e.g. set it to be 2.25" thick when it is really .75" thick) and write a file using the zero-ing post processor. Second choice - create a separate output file (or files) and use the “no-zero” post processor, and manually set Z-zero to be somewhere above the actual surface of the material, run that file and when it is all good run the one with the z-zero code baked in. Anytime I post any tool paths out, I make a folder for auto zero and a folder for no zero. That way if I need to manually correct something on the fly or do an air pass, I just go to the no zero folder.

Q: I'm looking to make some 6mm slots and was wondering whether to get a 1/4" or 3/16" shank bit. I figure the latter allows deeper contours.

:A: 3/16" is getting into fragile territory. Control your feeds and make sure you're checking that the dust is clearing out of the slots. Pause the job periodically and break up any compacted dust with a thin rod; vacuuming it out is a plus. The danger here is not to the ShopBot but that you can easily snap your bit. An up-spiral bit would do better at clearing chips but will produce poorer cut quality.

Q: Can I output from Fusion 360 to the ShopBot?

:A: Fusion has a driver called OpenSBP, which works fine. I used it this afternoon to do a cut, and if my measurements had been more accurate it would have been a Success. You have to do the manual Z-Zeroing for each tool, so having your Origin at the lower left will be Best Practice. Note our ShopBot doesn't have a software-controlled spindle speed or on/off.

Q: While moving one of the axis will struggle in spots and lose its position.

:A: Our Shopbot cannot tolerate a jog speed of more than 4 inches per second. Reduce the jog speed and the problem should go away.

Q: A simple rectangular part I cut out measured about 0.85 mm longer and wider than expected. Meanwhile, the dado slots I cut into the face of said part measured about 0.4 mm narrower than expected.

:A: There are three issues that cause dimensional inaccuracies, the most common is running the Shopbot too fast. It is an open-loop system so it has no feedback to say that it missed steps. The 2nd is errors in the translation from the drawing to the Shopbot part file; I would inspect the file and see if the dimensions seem correct. The 3rd is setting a bit diameter that does not match the physical bit; I would measure the bit to insure it really is 1/4”

Q: What is the Shopbot zeroing process for Fusion360 files?
:A: Short version (easy way). Set your origin In Fusion to the bottom of your stock, at the lower left corner. Use C3 to zero the Shobot’s X and Y. Load your part, and the cutting tool. Move the spindle to X=-2, Y=11 and then use the C2 function to zero the tool TO THE SURFACE OF THE TABLE. run your file. clean up the mess. Watch [https://www.youtube.com/playlist?list=PLmhqMIFhtr9QpW6BFizdXsYAUiMjvNrT2 video's numbered 4 and 7].

Shopbot and Tormak

2022-12-17T17:36:32Z

JeffG:

<div class="postbody"><div id="post_content35"><div class="postbody"><div id="post_content32">
= Device Manufacturers=

* ShopBot [http://www.shopbottools.com/ website] - The classic CNC wood router. Tabletop to 4x8. Shopbot ALpha is 4x4 foot.
* Iconic CNC [http://iconiccnc.com/products/ website] - Midsize CNC routers

= Maker Nexus Equipment =

The Maker Nexus woodshop has a [https://www.shopbottools.com/products/standard ShopBot PRSstandard 48-48] with an effective work area of 48" x 48" for cutting soft materials such as wood and plastic. The shop has chucks for mounting 1/8", 1/4", 3/8", or 1/2" tools. There is no automatic tool changer. Spindle speed must be adjusted manually. Jog speed must be no more than 4 ips or the machine will lose position.

= Software =

To prepare your design for cutting you need to create "tool paths" for the target machine. In software you define the material your part will be cut from, the tools (bits) you will be using, and the speeds and feeds for each tool.

* V-Carve is provided by ShopBot to create toolpaths. A limited feature version is available for members to run at home to prepare their files for generating a cut file. Then you create the cut file on a full featured version at Maker Nexus. You can save a 2D file as .dxf and then import into VCarve.

* Fusion 360 can also create [https://www.autodesk.com/products/fusion-360/blog/getting-started-introduction-to-cam-and-toolpaths/ Toolpaths]. However the free version of Fusion 360 all the rapid moves (G00) to G01 as an incentive to upgrade to a paid version. So your cut file will take longer to run if you create it with the free version of Fusion 360. If cutting on the Shopbot, you can press (Shift + "." = >) to speed up the Feed Rates.

= Techniques =

ShopBot specific tips can be found at [[ShopBot tips]].

== Speeds and Feeds ==
Wikipedia has a good page on speeds and feeds. In particular, you can get the cutting speeds for many materials using a high speed steel cutter. [http://en.wikipedia.org/wiki/Speeds_and_feeds http://en.wikipedia.org/wiki/Speeds_and_feeds] Missing from the Wikipedia table is Wood. The Cutting Speed for a soft wood, such as pine, is 1000 feet per minute.

There is a recommended speeds and feeds calculator at [http://www.custompartnet.com/calculator/milling-speed-and-feed http://www.custompartnet.com/calculator ... d-and-feed] The calculator needs Feed per Tooth. We were told to use the following values:
*Aluminum: 1/100th the bit diameter
*Wood: 1/50th the bit diameter
*Foam: 0.1
Plunge speed should be about 1/3 the feed rate.

Most router bit specs have feed recommendations. Amana router bits also specify the material type. They have bits for wood, plastic, stone, metal, etc.

== Problems when cutting ==
If your wood part smokes, then either increase the feed rate or slow the spindle RPM. If you hear screeching, they you are feeding to fast - or too slow. Try slowing the feedrate first. If that doesn't work, then increase the feed rate a bit.

= Supplies =

== Bits ==

The shop keeps a few bits on hand for classes and for resurfacing the spoil board but you should purchase your own bits to avoid damaging the shop's tools and ensure consistent results for your projects.

The more flutes a bit has, the more heat it generates. Typical flutes for materials:
*Plastic: 2
*Wood: 1 or 2
*Aluminum: 2
*Steel: 4

CNC router bits are different from handheld router bits. They are driven through material by a rigid gantry whereas handheld router bits follow a path using a guide bearing. Be sure to buy the right kind of bit.

Dan-Mar Tools is a good source of bits 907 American Street, San Carlos, CA 94070 Phone:(650) 591-2651For cutting pink foam, Matthew had a four inch long bit that was about 0.5 inch in diameter. The flutes were almost like a rasp on it. He said it would just rip thought the foam at very high speed. Great for a roughing pass.

You can also purchase bits online from Amazon and other retailers. Carbide bits last longer than high speed steel but are much more expensive and brittle (don't drop them!). Some manufacturers offer complementary sets of bits at a modest discount to get your collection started, such as [https://makermade.com/product/router-bit-5-pc-combo-pack/ MakerMade], [https://www.whitesiderouterbits.com/collections/cnc-sets Whiteside], and [https://www.freudtools.com/explore/router-cnc/router-bit-sets/cnc-bit-sets Freud].

= Materials =

== Pink Foam ==
I bought 4x8 sheets of two-inch thick pink foam insulation at Home Depot. Not every HD carried it. The sheets where scored half way through every 18 inches. This material cut extremely well. I sprayed the finished piece with shellack. For a more spooky effect I sprayed it with gray paint and the material started to dissolve away a bit.