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As a group do your lab's safety training test runout, alignment, fixturing, speeds, feeds, materials, and toolpaths for your machine.
You can see our results [here](https://fabacademy.org/2023/labs/charlotte/assignments/week08/). My take away is that CNC is a very
powerful machine and that the set up is much more complicated then I expected and is critical to the success of the cut as much
if not more then the design.
**Accomplishment**
This week I took on making a table that is 30inches high and 48 inches in diameter.
1. I designed a table using parametric approach to ensure we can easily adjust to the wood pieces we get that
doesn't use fasteners or glue
2. I learned how to use the manufacturing side of Fusion and make cut paths
3. I Made hardwood glue up panels for the first time and use the Festool Domino to install dowels to strengthen the boards
4. I learned how to run the Shopbot CNC and cut the table [Table top done, legs are in process]
I used the following picture as a basic inspiration for my table
Hight: I started by looking up hight for table and is seems that card and dinning tables are typically 28-32 inches high. Work
table are 28-30 inches and so I decided to go with 30 inches
able top size: I decided to go with the biggest I can make which is going to be 48 inches
Floor base: I found on line that the “golden rule” is to have the width of the base at the floor be at least 0.6x the overall
height of the table. As this is the minimum I wanted to have a very stable table and decided to use 0.75 as the ratio.
I plan to make this with a glue up of 3/4 inch hardwood planks (see next section)
First up a set up a few parameters I plan to use based on the design approach I listed above
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Circular patter repeat make this a quick one
Next I started on the legs and was wanted to ensure the end of the leg can slide into the the
slot in the table top
I set up the basic shape and mirrored in the sketch to ensure the legs were symmetrical - this was my
first mistake as a later found out that mirroring in the sketch does not work as well a mirroring
the extruded part when changing the user defined parameters
I got the legs ready with the cross fit joint
Next I decided to check fit in fusion and good thing I did as I has the slots misaligned
This called for a new parameter and I used sketch dimensions restriction to ensure they will line up
I used the same parameter in the top and leg to ensure alignment
and another check - we are good to go
Now that we get that working I decided I really did not like the look of the legs and so it was time for
design #2
I repeated the steps above and had the next set of legs ready
When I wanted to resize the legs the sketch profile kept coming apart and so after some research I decided to
redo this once again the this time to use the 3d mirroring instead of the sketch.
So here we go again
I extruded on this part
then mirrored it in 3D
duplicated and added joint
I downloaded a [Dogbone add-in](https://apps.autodesk.com/FUSION/en/Detail/Index?id=3534533763590670806&appLang=en&os=Win64) for Fusion and got the design ready to cut
and now we are ready to mock up in the laser cutter
## Laser cut mock up
Next I took the basic table design and laser cut a small version to get a feel for fit and look
The table looked nice and legs seem to align well to the table top slots
When I showed it to my kids they started playing with it and turn the legs upside down. This looked much
better!!!
Now I needed to get back to fusion and redesign the legs.
## Leg design #2
To ensure i keep the slot in place I created a plan on the bottom and projected the
slot on it
Then I saw that the leg was too narrow in that part
I extruded it but need to get the base back in line
So a went back to the sketch and adjusted it
That looked good
Now I needed to erase the old slot
and this looks
And we are good to go
## Cardboard test #2
Quick cut on laser
And I think we are ready to cut ...now we just need the wood glue up
## Partial parametric design
This was a struggle for me and I only had limited success.
Table top - this was pretty straight forward and thickness, slots side/location, and table top diameter were all working well.
Legs - here I hit a road block. Thickness and slot insert size worked well but when I tried the get the hight / width to work
I could not get it working.
I tried constricting the shape completely and it went all crazy.
I also tried scaling after I switch the mirroring in 3D vs. the sketch as I described above but still no go
I also replaced the arcs I used to curve the feet with filet but did not manage to make it work
I designed 2 other leg shapes and still could get it to change hight and keep the shape.
I was running out of time and decided to focus on Parametrics design for the slot and materials thickness that
are as most important for this design.
I got that work work and sync between the top and legs.
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## Wood glue up
Chatting with Dr. Taylor about the table he had a great suggestion of using a glue up of hardwood to take the
table to the next level. This was a great opportunity to learn 2 new things:
1. How to glue up hardwood panels
2. How to use the [Festool DOMINO Joiner](https://www.festoolusa.com/products/domino-joining-system/domino-joining-machines/576423---df-500-q-set-us) our lab has.
{: style="height:300px;width:300px"}
I headed out and got some nice wood planks
Next was the joiner to make sure the side were nice and flat
Next OI lined up all the planked to get the patters
I marked the planked every 8 inches for each place I will put a domino/dowel
Next step was the drill holes at every marking for the dominos/dowels
Here you can see the holes
Now I set up each plank put glue and inserted dominos/dowels
You can see how the line up
Now started to run through putting in wafter and then inserting next plank and stacking them together.
I found out that it is very important to have the dowels all the way in to ensure a smooth stacking and
so you can see I use a maleate to ensure all the dowel are in and then again to put in the next plank
My dad who is 86 was visiting and come into the shop to supervise as I was working. He introduced me to
woodworking when I was a childe and while his arthritis does not allow him to do any woodworking we had
a good time working together.
Next I moved to the glues panel to a flat surface and I use 4 long clamps to hold the planks together
in addition I use 2 metal bars and smaller clamps on each edge to keep the panel from bowing as much
as possible.
Another inspection approved
24 hours later the board was dry enough and loaded into my truck to free up the space to work on the next
panel for the legs
I repeated all the steps above and now panel #2 is drying
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## Getting files ready to cut
First I needed to add a tool library and the shopbot to post processing.
**Tool library**
You first need to downloaded the tool file [here]( https://www.amanatool.com/cnc-tool-databases-for-fusion-360tm-vectric)
Then you start with the tool library
In local library you right click, click import and select the file you downloaded
and now you should see the new library show up
**Post processing**
Fusion 360 post processing file for shopbot you can find [HERE](https://cam.autodesk.com/hsmposts?p=shopbot)
You start with the Post library
Then you click import and select the file you downloaded
and now you should see the shopbot options show up
This set up was set up was shared with me by Dylan Ferro and you can see more detail in his page [here](https://fabacademy.org/2023/labs/charlotte/students/dylan-ferro/lessons/week7/)
**Cut paths set up**
So now we move into the manufacturing side of Fusion and started a new set up
We first needed to choose the Stock point. You can see little while dots on all corners. This
will be the starting point to zero the shopbot/start the cut. I choose the bottom left corner.
Made sure the axis were set up in line with the machine
Next we to set the stock - I choose Fixed stock from the drop down and put in the measurement
48 x 50 x 0.755
Finally need to set up a number/name for file and description
And we can see the set up is done.
Now we need to set up the tool paths - I was only cutting in this design so we needed "2D contours" and first
thing we need to do is select the bit - 1/2 inch end mill
Next you need to choose the outline for the cut you have a number of option but I ended up use Chain
and selecting the bottom profile of the shapes
Next we need to put in the tabs - discussing the shape I was cutting with my instructors they 12 inches and 0.25 inches
To be on the safe side I increased the clearance hight to 2 inches and retract highest to 0.5 inches. My instructor suggest
I add -0.02 to the bottom to ensure a cut through
We set the cut depth to a little more then half of the drill bit size from 0.125 to 0.27
Here we made 2 changes, the Lead in angle to 0 and on the Ramp Angle to 2. This was aimed to ensure we do not have any unplanned
marks left by the tool.
Any finally we ran the simulation to make sure it all looked good and then proceeded to Post process and exporet the cut file.
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## CNC cuts
**Workflow:** I pretty much following the following work flow we use in the lab
You can see the detailed steps [Here](../files/Week7/ShopbotWorkflowMarch162021.pdf)
At a high level we had to follow these steps:
**Bit**
First we had to install the right bit.
**Loading**
Loaded the board and attached it in place
**X Y Z**
Zero out the X, Y and Z.
**Air cut**
Loaded the cut path and ran the cut in the "air" above the board to ensure
everything looks right
**Run the cut**
The tabs did their job and we have a table top
## Finishing and assembly
**Sanding**
Now it is time to sand
**BEFORE**
**AFTER**
The legs went on relatively easily
When it came to the top it turned out that one of the cut in the slot was not flush and requireed some sanding
An here is the final product!!
Files for the week [Shopbot](../files/Week7/Cutfiles.zip) and [Design](../files/Week7/Table.zip)