Assignment: Group: test runout, alignment, speeds, feeds, and toolpaths for your machine. Individual: make something big Learning outcomes: Document the process of design and production to demonstrate correct workflows and identify areas for improvement if needed Assessment: Have you:

a) Explained how you made your files for machining (2D or 3D),

b) Shown how you made something BIG (setting up the machine, using fixings, testing joints, adjusting feeds and speeds, depth of cut etc)

c) Described problems and how you fixed them, and d) Included your design files and ‘hero shot’ photos of final object

Summary

• Tests Run using the Shopbot PRSalpha and Stepcraft 2-300
• Brainstorm and Design
• Design In Librecad
• Options -->current drawing preference --> milimeters / General Scale 20 / Length Factor 1
• line - 2 points /horizontal /vertical
• circle- 2 points and center radius
• polyline- creating polyline from exsisting segments
• copy / duplicate
• divde for making the dogbones
• Shopbot Parameters
• Outside Cut
• Cut Dept 10.75 for 9mm material
• Passes 2
• Tool Dia 6.0
• Spindle Spee 14000
• Feed Rate 120.0 mm/s
• Plunge rate 15.0mm/s
• Tabs
• Inside Cut
• Passes 1
• No Tabs
• Assemble

For this weeks assigmnent we had to use the cnc machine to make something big.The downside for us here in suriname was that initially we did not have access to a working cnc machine so we had to go back and forth between two semi avalible machines at two different locations. The stepcraft D840 at the iot lab and the Shopbot PRSalpha 96-48-8 at the fab lab suriname.

We started off doing our tests using the shopbot in the fab lab suriname.The first thing which we did was to buy our material we had 9mm plywood and 8.5mm mdf.

The next thing we did was get to know the Shopbot PRSalpha 96-48-8. We got guided through the physical setting and software set up of the shopbot before using it.

Before getting started using the stepcraft we had to keep in mind the safty rules before going in and getting busy. We had to make sure we had

Saftey goggles to protect your eyes from dust

Ear Buds/Piece for the noise

Mouth cap so you dont breath in toxic fumes

After putting our safty gears on we went and select which material we wanted to do our test on. We started off using the 9mm plywood and tacked it in on the shopbot base plate.

We were then guided by the fab lab suriname manager on how to go about starting the shopbot. We had to first go around to the left side of the shopbot and as you can see below first switch the key to the right , then switch the second lever to the right to engauge the machine then press the green reset button to rest the shopbot.

Shopbot Shopbot PRSalpha 96-48-8 Setup

Physical

Switch Key

Engauge Switch

Reset Button

Calibrate

Once the shopbot was physically ready we went to configure the software. For using the shopbot the recomented software to use by our lab manager was Vcarve or Aspire for converting our svg or dfx files into spb files and the Shopbot software for reading the spb file and turining it into coordinates to control and positon the shopbot.

When using vcarve and aspire to impot my dxf file from librecad I initially had alot of issues because vcarve and aspire was reading lines that I could not see was there for example extra layers.It was making a mess of the preview cut. I then trouble shoot the problem and realized that when exporting my dxf file from librecad I had to make sure I did not have additional layers instead just one layer with my design and I also had to make sure I made polyline of each segment of my design so that all the lines were closed. Then when I went ahead and imported it into vcarve and aspire I had no problems.

I then went ahead and add my

cut dept

passes

tool diameter

spindle speed

feedrate

for my testing (you can see below all the individual tests with parameter we did) and preview the cuts and it looked fine.

After exporting my spb file. I then went ahead and open the shopbot software and position the shop bot x and y position to 0 and under Cut I set it as home position.

And also manually set the Z axis to zero. For setting the z axix to zero we had to take the silver plate put it on the base plate and connect the clamp to the spindle and via the software lower the spindle until it touches the plate and recalibrate.

Set home x0 yx

Manually set the bit and zero Z axis Plate

Software

Apply parameter in Aspire and export to sbp

After the shopbot was ready I then had to navigate to my spb file and import it into the shopbot,

Import into shopbot

Manually turn spindle on

I then went around and turn the spindle on on the side of the shopbot using the green button on the box.

I then went back to the shopbot software and click start a popup with appear to confirm if you want to continue with the procedure. You then check with whoever is watching over the machine if its you or a collegue. Check if they are at a good distance from the machine and if they have their safty gear on and if they have the emergeny switch in their hand to push incase of emergency.

Press start on software on pop up box

Then you go ahead and confirm and press start

Press start

Once your procedure is completed you can go ahead and add another partfile and repeat or you can change the zero position if you would like to do your second procedure on another zero position.

Repeat on loading another partfile

If you see below these are a few tests we made using the shopbot. On the table is the Aspire parameters we used for creating out spb file.

Test 1 Shopbot 8mm plywood

SHOPBOT CNC	Selected
Cut Depth	10
Spindle	2600
Feed Rate	100
Plunge Rate 30	2.0000
Pass dept	0.125
Passes	4

Test 2 Shopbot mdf

SHOPBOT CNC	Selected
Cut Depth	11.2
Spindle	12000
Feed Rate	125
Plunge Rate	30
Pass dept	0.125
Passes	4

Stepcraft D840	Selected
Tool Dia	6
Target Dept	-9
Outside Cut
Saftey height	15
Step down	3
Feed Rate	1500
Plunge Rate 1500	500

Shopbot Day 2	Test1
Plywood	9mm
Spindle Speed	12000
Feed Rate	62.5
Flute	1 straight
Passes	4
Climb
Bone inside	Square Outside

Result: Average

Shopbot	Test 2
Mdf	9mm
Spindle Speed	14000
Feed Rate	135
Flute	1 straight
Passes	2
Climb
Bone inside	Square Inside X mistake

Result: Burn through the cuts and rough edges

Shopbot	Test 3
Mdf	9mm
Spindle Speed	14000
Feed Rate	135 in/min
Flute	1 straight
Passes	3
Climb
Bone inside	Square outside cut

Result: Burn through the cuts

Shopbot	Test4
Mdf	9mm
Spindle Speed	12000
Feed Rate	62.5 in/min
Flute	1 straight
Passes	3
Climb
Bone inside	Square outside cut

Result: Bit was no longer good it burnt out.

Stepcraft D840

Generate gcode from dfx or svg

Import into Uccnc on stepcraft 800

Reposition x y positon on uccnc

Use z measuring sensor to measure the z axis

Leave the default stepcraft parameters

Override the travel speed by 70%

Manually switch the spindle on to stage 3 which is about 9000rpm

Start cycle

Stepcraft D840	Test5
Mdf	8.5mm
Spindle Speed	9000
Feed Rate	150 in gcode overrided in uccnc 70% in/min
Flute	3 straight
Passes	2
Bone inside	Square outside cut

Best cut so far / workable.

Our material was 8.5mm mdf so we designed our test bone to be the width of 9mm and the factor which we adjust was to scale the selected pieces the square and bone by a factor of 1.1706 to adjust for the difference which the stepcraft was giving which was 17% difference from the design and the actual cut. For the end result the width of the bone became 10.53 for the width of 9 mm in the design and 8.5 mm material thickness.

Designing the Greenhouse

I started off brainstorming a few ideas for this week assigmnent. I was going back and forth between either making a table, a press fit wall decoration or a small scale greenhouse version 1.0 for demoing my final project.

I decided to go with the latter. I realized that I will use the time wisly and make something I would actually need for my final project.I started off wanting to make a greenhouse which will look like a house and browse the internet alittle to get some ideas.

After going over a few designs I realize that I wanted to keep the design simple because I am still learning how to use the CAD tool Librecad to design my project.

I eventually decided I will make a press fit greenhouse which consists of 5 panels. Two for the sides and legs and 3 which will fit into the box in the middle

When designing the legs I initially wanted to do a A shaped leg so that it could keep the look of a house but later I decided to make the Legs C shaped and the top part to look like half of a circle so it keeps the look of the greenhouse.

I decided to make the two sides with legs and top the same just fliping one side the opposite direciton so that it balances itsel when standing.

We had to keep in mind the size of the CNC machine we had avalible to use here in Suriname.We might have access to the Shopbot from the Government lab which could take the size of a full sheet of plywood 244cm x 122cm or the cnc machine from the iot lab which could take only half the size of the sheet of plywood estimated to be safe 80cm x50cm.Since I was not quite sure which machine we would have access to I decided to scale my design somewhere in the middle.

I initially scaled my projects total height to be 100cm height and width to be 45cm and lenght 70cm

The two sides will be 100cm x 45cm. The based box will be 45cm wide 70 height and 25 cm debth. The inner box will consist of 3 panels the base is 70cm x 45xm and the two sides will be 70cm x 25cm. I designed all the parts to be pressfit so that it could nicly fit together without glue or nails. But because we were going back and forth between which machine we would be using I decided to scale down my project to fit the stepcraft dimention between 80mm x 50mm to be on the safe side.As you can see below you can see I adjusted the sides height first from 100cm to 90cm and then 75 cm I will explain more about the reason why I changed the leg width below.

Designing in Librecad

When working with Librecad for designing my greenhouse in 2d it was pretty straight forward. I started of my navigating to current drawing preferences and changes my dimentions to milimeter and put general scale to 20 so that I can see my units clearly when im measuring my pieces and lenght factor to 1 so that it starts measuring from 1.

Options -->current drawing preference --> milimeters / General Scale 20 / Length Factor 1

The tools which I used the most was

line - 2 points /horizontal /vertical

circle- 2 points and center radius

polyline- creating polyline from exsisting segments

copy / duplicate

divde for making the dogbones

The most complex things we had to make this week was the dogbone to fit our piece so if you can see below I added a simple guide on how to make the dogbone using librecad.You have to make the width of your rectangle the width of your fitted piece and the height the thickness of your material. You then add use the paralell tool from the side of the height of your pocket and put in the parameter of the radius of your tool bit.Mine for example was 6.35/2.I then add a center radius circle from the center of the parallel line within the rectangle.I then went ahead and divided my lines and remove the exsessive lines and continued on all four corners to make my dogbone. See below

After designing my first pieces in Librecad and we did not yet had access to the cnc machine I wanted a way to fit the pieces together to see if I got the dimentions correctly so what I had to do was export my pieces from librecad as svg and import it into Tinkercad.

But keep in mind it was not as simple as it sounds.I had to make a few mistakes before it actually worked.
The first thing is tinker only acceps stl svg and obj file formats. When I tried exporting my pieces all at once as svg from librecad and import it into tinkercad I had 3 issues one my files were too big so I had to scale it down to 10 percent(note this only scales general height and width not the thickness of your material so you will end up having chucky looking pieces).

Secondly, all my pieces were grouped into one object instead of seperate pieces and
Third my pieces were broken and not as it should be.

The solution which I came up with was to
1 I had to in librecad Select each piece and CREATE POLYLINE FROM EXSISTING SEGMENT so that my pieces were no longer broken into pieces but grouped at one shape and 2 to get my pieces to be exported seperatly I had to literally save each part of my project seperatly as individually svg files and then one by one import it into Tinkercad.It was a tedious workflow but when I got used to it I enjoyed it.

If you can see below there is the imported version of my first design into tinkercad.As you can see I realized there were two problems one I had to manually scale the thickness of my material this is how it look when it was not scaled and two I realzied that when designing the width of the legs I forgot to keep in mind the thickness of the two end panels so they did not fit I had to then go back and adjust the width of my leg from 45cm to 50cm.

After adjusting the width of my leg my instructor told us if we will be using the stepcraft c300 for cutting our pieces the best dimentions to keep our design within is 80cm x 50cm so I had to then go ahead and resize my leg because we still did not know if we were going to get access to the shopbox which could take the size of the full triplex. So as you can see below I scale down the size of the leg from initially 100cm to 75cm.

And I was also not sure which of the machines -material or tool bit we were going to use so I design my files for both 8mm and 9 mm wood with the two tool diameter we might possibly use one with 6 diameter and 6.35 diameter tool and the leg height either 75 for stepcraft or 90 for shopbot.Its hilarious I know.xD

I then went back and forth a few times simulating in tinkercad how my greenhouse would look like.When I assembled my design in tinkercad I realized my design actually looked like a baby cradle.Everyone thought it was a baby cradle so I also tried channging the top part from a half circle to look more like a house triangle but eventually because I was running out of time I actually went back to the half circular top.

After assembling my pieces 3d in tinkercad I wanted to know how it would look if I actually add the texture of the plywood we had here in Suriname so I went and took an image of the plywood we have here uploaded it to my laptop. I then imported my exported stl file from tinkercad and imported it into fusion 360. I then went and added a blank wood texture for the appearance of my greenhouse and added the imaged I made of the plywood as the image for the selected texture and rendered it. I tried it with combination of maple semi glossy and mahogany semi glossy texture as you can see below it looked nice.

Cutting wit the CNC

The Day has finally come when the ShopBot from Kkf started to work!!!

The last and final test was performed successfully by our instructor and fab lab manager and they realized why the cnc machine was cutting our pieces so ugly and also burning the pieces and the bit.

The Spindle was installed wrong and turning COUNTERCLOCKWISE!!!

After having done so many tests and almost giving up on the shopbot our instructuor gave it one more try and found out the spindle was going counterclockwise instead of clockwise. After installing the spindle to rotate clockwise our tests cut came out perfectly and I was then able to cut out my project.

I then went ahead and exported my design from Librecad as dxf file and removed all my layers I just kept the mail layer.If you keep the unnessasary layers it will make it hard for aspire or vcarve to read. I also removed the sticks for reinforce my pices to stick together becasude I think it makes my design look to patchy.

I then open my dxf file into Aspire and added the Shopbot paramters.
The material which I was using was

9mm

cut dept 10.75

because the shopbot was miscalculating the cut dept by almost 2 mm.
I choose to run 2 passes so every pass will cut into 5.375 mm of the material.
Pieces to be cut outside and bone inside with same parameters but the bones i added no tabs
Tool Diameter was 6.0 mm
Spindle speed was 14000
Feed Rate 120.0 mm/s
Plunge rate 15.0 mm/s
I also added 4.0mm tabs so that when the shopbot is running the cuts the pieces does not get loose note: make sure to select the correct shopbot from the dropdown menu mine is shopbot inches

I then went ahead and exported my 2 files as sbp files one outside.sbp and bones.sbp uploaded it into the shopbot .

I then reset the shopbot and then positioned my x0 z0 position and Z manually calculated

I then put my saftety gears on and watch my pieces cut. It was very clean

Lessons

I want to start of by saying I learnt alot this week. For the design part I added the lessons I learnt when designing the dimentions of my pieces above in my explination so I will mention the lessons which I learnt which working with the Shopbot for cutting is to make sure you check your material thickness and be sure of it before designing your project because material thickness easily differs.

I lost alot of time having to redesign my bones because of the change of material thickness.

Make sure you check that all your extralines are removed and your layers are deleted when creating your sbp file. I made a mistake and forgot to remove an outline on one of my bones so when it went to cut the bones out all were cut nicly and one bone was missing. I had to then recut that bone but since I had already cut the piece out it was moving on the plate and the bone came out a mess.

Download Files Here

Greenhouse Libracad Dfx
Shopbot outside cut
Shopbot bones cut
Tinkercad obj
Tinkercad stl