Engraving Acrylic

Well it took some time but my Shapoko 2 is now a real machine that I am using for real products for people.  Please check out the photos below of what I have been up to.

More engraving stuff

The next photo is on a 3" mirror, I only have 80 of these to engrave in the next two weeks. Note that it is very hard to take a good photo of a mirror, so this photo doesn't do the engraving justice.

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F-engrave

F- engrave is a very good open source gcode generator for engraving. Below are a couple of photos of receient work I've done with mirrors using a spring loaded diamond spindal mount engraver. This is called Diamond Drag Engraving, no spindal rpm. 

Whistle while you work...

With the new aluminum table installed and everything now flat and square, I wanted to take a shot at milling something a bit more complex for my overal CNC education and to see what the Shapeoko 2 can really do in regards to precision.  The parts are for a Flat Nautical Whistle.  There are several depths that must remain constant and accurate. The radius for the completed parts also need to matchup otherwise the whistle will not work. So the real test is, will the whistle produce 3 separate tones when assembled.  Remarkably it worked, so well that I was asked to stop testing it! Please see the photos below. 

CNC Table

Well I wish I could say how easy this was but it took me an entire day to switch over to an all aluminum platen for the Shapeoko 2 CNC.  Broke a tap off In the last hole I was working on and it took almost 5 hours to recover from that mistake!!!  Without any adjustments the table is square forint to back and only out .005 side to side.  I will add some .002 shim stock and hopfully that will bethe end of that. Overall the the CNC is more rigid, but then again I haven't cut anything yet...

Refrigerator vent cover

So I was asked if I could make a new vent cover for a vintage Italian refrigarator. The acrylic and gray end parts were all cut on the Shapeoko 2 CNC. The lettering and icon were milled using a .023 carbaloide end mill. I placed plastic tape on the acrylic before milling, then painted the inside of the icon and lettering with automotive touch up paint before removing the plastic tape. I'm very happy with how the lettering and icon turned out.  The vent slots were cut using a .057 end mill. The entire part would not fit on the CNC so I had to reposition and reindex the acrylic to cut the vents and lettering (bigger CNC would be nice but not in the foreseeable future).  The person that owns the refrigarator was blown away with how good it looks.

Microscope

The photo below was taken with a microscope of a pocket cut.  The size of the cut is about 0.100. Notice that the top of the letter e is not there. This happened because I was using a V shaped cutter with an end point greater than 0.006 with a V angel of approx 35 degrees. The equivalent of using a hammer to thread a needle. I ordered some carbide end mills (square end) and some engraver bits (V end). Should look a lot better with the new end mills.  BTW the end mills are cheep, less than $10.00 

Oh, the microscope was set close to X100.

Next photo taken with IPad to give you a real eye view of the same cut

Broken CNC

Take a good look at the photo below. These are the brass Stand offs used to support the Z stepper motor. When I first put the CNC together I thought of how poor of a design using the stand offs to support a stepping motor. This story starts out with hearing what sounded like loose parts rattling on the CNC while fast traveling to a work position. Using the most sienctiffic analysis method possiable, I took my hand and held verious parts of the CNC to determine what was making the noise. Turns out the Z stepper was the source.  I did what every good technician would do, grabbed my  tools and started tightening bolts and of course the brass stand offs. One of the stand offs appeared to be loose so I tightened and I tightened until,"SNAP". Yes, I broke the threaded portion off in the Z stepper.... Unfortunately I have a reputation of over I tightening just about everything, so in my case it's either TIGHT or  it's BROKEN!   After taking the Z axis apart, I measured the length of the stand offs and found there to be a .010 difference in length.  I ordered new stand offs (they come 20 in a pack) and decided to measure them.  They are all different, close in many cases but different lengths by a few thousands here and there.  With this new information I decided to make my own version of stand offs for the Z axis (see second photo). The results were fantastic! With all three Stan's offs now having identical lengths the CNC runs much quieter when fast traveling to verious locations on the CNC. Once again SUCCESS at the cost of breaking something.  

Linux software

So After we talked last night i found the correct Linux version for the universal g code sender.  It works great. I also loaded Inkscape, f-engrave and libra cad.  All work fantastic on Linux!!!!!   Now I have to figure out how to get my windows files from those applications copied and loaded to Linux.  Now I'm happy!

Nuts

The photo below shows the approximate position of the concentric nut when tightened appropriately. Because the V wheels are made of nylon, over tightening will cause the wheels to bind and possiably leave flats in the nylon. Too bad the metal wheels are so expensive, also need to consider how the metal wheels will ware on the rails.

Adjustments when setting up

This is going to look like a lot of effort but please take the time and read my suggestions so that you are able to start milling with minimal issues.  There are probably several approaches to squaring but this is what worked for me.  Like GrandPa Elwartowski used to tell me when I worked for him at his shop... You can't re-drill the hole after you drilled it, so make sure you get everything lined up correctly to start out, then the next 10,000 holes will be a cinch to drill.  The thought of drilling of 10,000 holes didn't make me happy but he was right about how well everything worked after getting everything squared up.

Here are some of the things that I needed to do:

1) Start out with everything loose. Only the top Vwheels should be tight.

2) I haven't used any locktight and don't plan on doing so until I get to a point where I feel the machine is usable whithout further modifications. I am very close to that point now.

3) the bottom Vwheels should be adjusted so that a small piece of paper fits between the rail and the wheel. This will probably leave a gap when the paper is removed.  This is ok because you need everything loose to square things up.

4) also make sure that all 4 of the Y rail end plates are loose. Snug is Ok.  

5) the y rail end plates should not be tightend to the bottom 1 inch square rail that holds the platen (i.e. Waste board).  Ideally both of the waste board rails and waste boards should be removed for the next step, but if you can ensure the Y rail end plates will not haing up on the 1inch rails then proceed.

6) you should position your assembly ( without 1inch rails and waste bords) on a flat surface. This truly means flat, so if your flat surface is out by let's say 10 thousands then your setup will also be out. Note you can compensate later but it's much tougher after the fact. Think, table top, counter surface or anything that you can put a straight edge on and not see any gaps under the straight edge. Remember to check the straight edge in two different directions.

7) ok, with the assembly on a certified flat surface you are ready onto start the squaring process. You need to measure down from the top of the rail to the surface in 4 separate locations close to the end plates. Those measurements need to be as close as possiable to each other ( 1 to 2 thousands is great). Once you are convinced that all 4 measurements are equal then tighten all 4 Y rail end plates. After you tighten then check your measurements again. Keep doing this until you get it right as you will be very thankfull in the end.

8) Now that the 4 end plates are square to your flat surface, you can put the 1 inch rails and waste board back on the CNC.

9) after putting the waste board back on the CNC re check the height of the Y rails to the surface of the waist board. If your 4 separate measurements are the same of within a couple of thousands then proceed. If not try adjusting the waste board rails. DO NOT TRY TO READJUST THE END PLATES AT THE Y RAILS, OTHERWISE YOU WILL NEED TO START ALL OVER.

10) NOTE for this step only the Top Vwheels of the gantry are tightened and the bottom Vwheels can be turned easily by hand without moving the gantry.   With the gantry placed somewhere near the center of the X rails, measure the distance between the two X rails front and back (you should measure as close to the Vwheels as possiable). Write your measurement down.  Move the gantry toward one end and take another set of measurements then do the same at the other end. You should now have two measurements for all three locations on the X rails center, left and right. Take all three sets of measurements and determine if they are close to each other, if they are then that is your measurement that you should end up with after tightening the end plates for the X rails. Re-measure after tightening and repeat until measurement is equal as you move the gantry from left to right.

11) there really isn't any adjustment for the height of the X rails from the milling surface, however measure down from the X rails at both ends and determine any difference. A couple of thousands out is great, anything more and you need to hunt where your are out.

12) now that you have the Y rail end plates squared along with the spacing between the X rails, you need to adjust the bottom V wheels on the Y and X rails.  I adjusted the non concentric nuts until I could no longer turn V wheel by hand then I backed off the adjustment very very very slightly ( about 1 degree of rotation).  Do this for all 8 of the bottom Vwheels on the Y and X axis.  

Now try moving the gantry around (left to right front to back) everything should move smoothly. If not start looking for problems with Vwheels or rails or something else.....

13) Now for the Z axis.  This time you start by adjusting the Vwheels first. After doing so take a machinist or carpenters square and place it on the wast board 90 degrees up to the side of the black mounting plate holding the grinder. You need to adjust the Z rail from the back until the black plate is square.  If you skip this step your end mills will only cut on one side and not the complete end.  This will make your finish flat milling not so flat.  At this point you should be able to easily turn the Z screw. By hand and move the z axis up and down.

14) using the machinist square check everything you an reach from the waste board. This includes the side Y rails, the X rails and everything you can get to on the Z axis. 

BTW sending you some stuff (tools and jigs) by UPS to help you with your set up.  

Before moving on to step 15 you can always call me and Bi#{[]. 

15) install the belts ( I will add more info on this step later).

16) Next is the wiring!!!

Making Progress ...

I finally spent some time lat night to get the X and Y axis put together and it is really starting to look like a CNC mill now. The X-axis slides smooth though I think I may have an issue with the Y-axis. The Y-axis slides smooth though it hangs in some spots as it is being moved. It is enough that I can feel it while moving the gantry. I quickly took a look at the V-wheels and found one that is wobbling so I think this may be the problem. I am going to try to remove the V-wheel temporarily to see if this is the issue and see if I can fix the wobble.

I guess the next step is to make sure it is square .. any tips? 

Time for a gear

Dewalt 611

Yea,  I upgraded to the Dewalt 611 after killing the dremal knock off that came with the kit.  WOW, what a difference!!!!!  Check out the photos below

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First attempt at engraving glass

The mirror is about 1" by 5/8".   I did not have a small enough diamond bit and I also should have adjusted my width slightly.  In any case I'm just glad it didn't shatter.

End mills

Starting to get a collection of end mills.

Limit switch options

Looking at the Sparkfun (http://www.sparkfun.com) new products page and found that they have a new selection of switches with mounts ... You can find it here: https://www.sparkfun.com/search/results?term=microswitch+mount.

Control box cover

This was my first attempt at cutting aluminum. Broke the first end mill feeding too fast!  Other than that the CNC performed ver well.  I just need to mount the fan and I'm done.

Coster

It took 4 separate g code files to create this coaster. I think it looks great but it would be much easer if the makercam.com allowed me to insert end mill changes. I understand there is software out there that will. In any case I learned allot about returning back to a job 0,0 starting point.  BTW this was cut out of an old scrap plywood.  If you looked at the bottom you would see paint and chips missing in the ply.  Next try I will use oak.

 

Limit switch

Above is the electrical solution I used for the limit switches.  The 330 ohm resistors are not an option as they are needed to pull the voltage up to 5vdc after the limit switches are added. Note that even though the limit switches are normally open they offer enough resistance to drop the voltage on the Arduino to about 4.87. The pull up resistors ensures a 5 volt TTl logic until the limit switch is grounded out. One important note: do not connect the ground for the limit switches to pin 14 as shown in GREEN in the photo, use the ground on the opposite side of the Arduino located next to the +5 pin.

In the above photo you can see a small board I added to my CNC control box. The board has the three 330 ohm resistors mounted (sorry the resistors are not visible this photo). The small board has 4 connections; one connects to + 5vdc on the Arduino and the other three connect to pins 9,10 and 11. You should also notice that these pins have two wires connected, one wire goes to the arduino as mentioned and the other wire goes out to the NORMALLY OPEN limit switch.

Good article on milling circuit boards

Got this is an email from Inventables .. good article about making circuite boards with the Shapeoko 2: http://blog.inventables.com/2014/02/circuit-board-milling-on-shapeoko-2.html

Cut2D Software: https://www.inventables.com/technologies/cut2d-15

http://www.easelcnc.com/

First real attempt at running a job.

My first attempt at doing something useful on the CNC. Unfortunately I did not compensate for the end mill diameter and cut out the inside of the letter "A".  The whole part was cut out of a larger scrap.  Not bad for a first try.  I need to make myself a check list before pushing send. The next try with the correct end mill will cut the same part along with the copper insets for the lettering and anchor,  maybe....... 

Harbor Freight $7.99

GRBL

https://github.com/grbl/grbl/wiki/Configuring-Grbl-v0.8

The above link is a MUST read providing vast info on CNC G Code commands and the controller we are using.  Ever wonder how to identify your CNC machine center on star up. Or how the hard limits work.  This write up in in GITHUB will answer those questions and more.

Threaded rod

This is what the threaded rod on the Z axis looks like when I spin it. Not sure if this acceptable or not for attaching the spindle carriage. It looks like it may be corrected when the rod is threaded in to the nut on the carriage but I really do not want to mess up the nut or the rod. I think I may take the rod out and see if I can get it to run straight.

Z axis partially completed

The Z axis spindle carriage and slide rail are put together ... Though I think I may need to adjust or move the nuts for the Z axis threaded rod. The rod does not spin straight and has a slight wobble to it though it does not hit anything when I turn it.

Setting Motor Current

Check out the following link on how to adjust the current on your grblshield.

https://github.com/synthetos/grblShield/wiki/Using-grblShield

Clockwise increases current, counter-clockwise decreases current.....

Pen test

Pen test went very well!!!!    I'll write more about my overall findings including an overheating z axis stepper.  That's everyone's problem or you might call it my current problem...  More to come on this.

More wiring

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I used 1/4 plastic tubing to protect the wire on one of the y axis stepper motors.  The tubing snaps nicely into the extrusion.