7. Computer Controlled Machining

This week i have designed , milled and assembled a simple podium using the ShopBot machine and V-Curve Pro as the tool path generation software along with the ShopBot driver.I have choosed Shopbot because it works mainly for such kinds of furniture works.

Though the machine is user friendly, i had to be cautious everytime and its needs attention and using Personal Protective Equipment(PPE) was must for my own safety.I had to follow all the instructions given by my local instructors to operate the machine as the machine is different from the one back at my place.

Assignments for week 7:

1. Group Assignment

Do your lab’s safety training, test runout, alignment, fixturing, speeds, feeds, materials, and toolpaths for your machine

2. Individual Assignment

Make (design+mill+assemble) something big (~meter-scale)

extra credit: don’t use fasteners or glue

extra credit: include curved surfaces

1. Group Assignment.

Group Assignment link is here

Learnings outcomes from the group assignment:

• It was mendatory to wear Personal Protective Equipment(PPE) while operating the machine.

• Always be attentive when the machine is in run and one authorized operator should be present and should not leave machine alone while running.

• I had to make sure that i am near and always ready to switch on emergency switch or control Pendant and the “Machine ON” and ‘Engage switch’.

• Use of sacrificial layer board is must for the safety and it must be cleaned properly and fix the job piece on it with bar clamps properly.

• While using the ShopBot driver to operate make sure i understand all the axis and functions of the panel and better to run in air as trial before actual operation by setting Z-axis in air.

• Do not forget to check the end mill with its collet and spindle and always fix back the dust shroud to make the dust particles to help reach to the dust sack.

• While doing job piece set up and tool path generation using the V-Curve Pro software, use Dog-bone for the inner slots and to cut inner slots of surfaces, choose ‘Inside’ option for machine vectors.And use features like taps and for external cuts to make it safe without disturbing the opration.

• Make sure we give correct pass settings like i had use half of the end mill diameter for each passes.

2. Individual Assignment.

A. Designing of Podium.

For this assignmnent i am using fusion 360 as i am familiar with it.

I opened Fusion 360 and clicked to ‘SKETCH’ and choosed the Top Plane.I have first drawn 700mm line horizontally for the base of the arm.

I added three lines, parallel to first line without dimensions.Then, clicked on ‘Sketch Dimension’ under “CREATE’ to give the dimensions to those three lines.

Next, drawn a vertical center line from 700mm line and gave select to offset 100mm to each sides.

Similarly, drawn vertical lines towards the base part of arm and gave their dimensions.

I selcted ‘TRIM’ command to look into shape.

I have done offset for the center verticle line by 6 mm to both sides to make the slot joint of length 500mm from the base and trimmed the unwanted lines.

Next, i have drawn line from the center towards the end and have drawn a circle with diameter 170mm and clicked on mirror command.

I trimmed the unwanted parts and added fillets for the arc and corner.

Then, i choosed construction line to draw from center and offset 12mm from top line. I gave dimensions for the vertical lines to make slots and trimmed the unwanted parts.

Now, i had to clicked on ‘Move/copy’ option under the “MODIFY” and select the copy option and dragged to make a copy of the frame.

After that, i mirrored the slot joint for the second frame as i wanted to add the slot joint on top.I clicked “Finish Sketch” and extruded the frames by 12mm.

Next i had changed the pattern with lines at center to triangular and trimmed unwanted and was mirrored.I made same changes to other frame too.

I haved made fillet for center pattern points with 30mm and drawn circles of diameter 150mm to the base of frame to add pattern.

I trimmed those base circles into halves.Next,to make slots to fix with frame, drawn a rectangle of 150mm by 12mm and clicked on ‘Move/copy’ command under “MODIFY” and dragged to copy with gap 100mm.

To add same slots horizontally, first drawn center line and drawn a rectangle horizontally and kept its distance 50mm from center of vertical line.Then i mirrored it.

I continued to draw outer rectangle for those slots by keeping distance 0f 75mm from all corners.

Drawn a line of distance 20mm and offset it by 12mm, followed by drawing center vertical line and trimmed the half part.

Next, i have drawn the outer supports for fro right and left sides.

For those two side supports above, i had made slots to both sides to the 550mm by 550mm frame with dimensions below.

I had drawn the last part with the dimensions below, with slot till half of 550mm and applied mirror command.

For the above part, i had applied fillet with radius 10mm for all.

That was the end of design for my stand.So i clicked to ‘Finsih Sketch’ and extruded it by 12mm to visualize and to verify by assembling.

To verify with assembly, first i had selected all the bodies and clicked on it to create components from bodies and clicked ‘Arrange’ under “MODIFY”.

Arranged the bodies according to the positions by rotating respectively.

After that, i clicked on “Joint” under “ASSEMBLE” and clicked to snap part A1 with A2.Similarly, i have joint parts C, D1 and D2 to their slots on part B.

Finally my assembled bodies for my stand looked as below and save my design files in fusion format as well in DXF format.

B. Milling using ShopBot.

Specification for ShopBot:

 . Standard tool accommodates sheet material up to 4’ x 8’ with cutting/machining depth (Z-axis) of 6 inches.

 . Table size approximately 6’ by 10’.

 . Step resolution is .0005” or better depending on gear ratio.

 . Positioning accuracy is +/-.005” or better (no load).

 . Positioning repeatability +/-.003” or better (no load).

 . Cutting accuracy is approximately +/-.015” for heavy cutting applications.

 . X, Y rapid positioning speeds (‘jogging’) up to 600” (standard)/1800” (alpha) per minute.

 . Z axis move speed up to 360” per minute.

Source from group assignment

Firstly, i Collected all the available Personal Protective Equipment(PPE) like hand gloves, ear muff, safety goggles, mask and ofcourse safety shoes for my own safety.

image from group assignment

I checked if the blower and its accessories are working so that the dust are safely sweeped to its storage.

Then, followed by cleaning the sacrifical layer using vacuum cleaner, ensuring particles not to affect its label for machining.I placed and fixed the (2400X1200X12)mm particle board with bar clamps.

I went towards the “Machine ON” and ‘Engage’ switches and put ‘ON’ clockwise the ‘Machine ON’ switch. I removed the collet wrenches from the ‘Engage Swith’, keeping it off and fixed 1/4 inch of 4 flute End mill bit to its collet and then to the spindle using the collet wrenches.

After fixing the end mill to the spindle, i turned ‘ON’ the engage key.

Now, i opened the ShopBot driver and clicked on the ShopBot keypad.I jogged to the X, Y and Z axes by carefully identifying their positions.

In order to set X and Y axes to zero, i jogged X and Y axes to the point and made it Clicking to the Zero Axes option and click tick to the x and y, where it becomes zero readings to X and Y.

Next i have to set Z zero.So i clicked on ShopBot keypad, choosing Z axis and placed the Z zero Aluminium plate on the jop piece and the other end connection to the spindle.

When plate is ready click to do Z-zero and again click ‘OK’ when finished with Z-zero.

After setting all the axes, i opened V-Curce Pro Software and did job piece sheet up by selecting the ‘Create new file’ option.Then imported my DXF file.

I have selected the top frame.For this, i clicked to maKe ‘Dog-bone’ for all that require with radius 2mm.

Next, i have selected all inner slots and did offset by 0.25mm outside to work as clearance.

Select line command to draw lines to and delate the outer parts and select those and go to tool path generation.

I did the following settings of tooth paths and clicked to calculate.

Now, click ok and click to view preset and again go to 2D for outer frames.

Follow same process but for outer frames, delate inner slots and for tool path settings ticked outside under machine vector and add taps here to prevent moving during machining.

Select both profiles and clicked on save and clicked save tool paths and save the file to one of folder to cut in the machine.

Now, open the ShopBot driver and follow the process below.

A dialog box will appear right after.Before pressing on this, Pressed start button on the control switch first to run spindle.Followed by clicked on ‘OK’ on dialob box.It started to run.

I followed same process for main frames by adding Dog-bones to inner slots and machine vectors as inside and for outer profile cut adding the taps of 2mm.

For machining, i followed same steps as above keeping in mind the safety precautions as well.

But unfortunately in middle of operation, a 1/4 inch end mill of 4 flutes was broken as the system got hang.There was no hazards to the machine accesories and the people.i called upon my friends and changed the bit but with older one.

My main frames were finished cutting but it was not good finishing as the end mill bit was old.

C. Assembling parts

I followed my assembling idea to assemble the parts

By referring above, i assemblied frames A1 and A2 along the slot joints.

Next, assembled part B with assemblied Main frame, joining from their slots.

Followed by joining part C on part B.

Next assemblled parts D1 & D2 with part B slots.

Finally it looked like this.

My Learning outcomes from this individual assignment.

• Always use PPE while operating the ShopBot machine and make sure i refer all the safety instructions displayed.

Give correct job piece set up and tool paths for my design and use proper taps and set passes wherever necessary.

Always be attentive with the machine while running and be ready to swith emergency switches if hazards occur.

Design files for week 7

1. My fusion file for stand for week 7 is here

2. My DXF file for stand for week 7 is here