6. Large format CNC (computer controlled Machining)¶
This week is as what instructor said the most difficult week but with help of expreinced instructor we could complete our designs. Our designs are about kids furniture which is interesting ! , but to be honest it was not easy for me, hold on keep reading and see what happened with me :) .
## What is a CNC machine? CNC machine (computer controlled control machine) or a subtractive manufacturing process that typically is computer-controlled automated control of machining equipment (such as drills, lathes, mills, and 3D printers). It processes a piece of material (metal, plastic, wood, ceramic, or composite) to fit specifications by pre-programmed computer software dictates the movement of factory tools and machinery without the use of a manual operator.
CNC has important information to know before implementing any project with Link of group assignment
, for this week we’ll be using End mill bits. It works by drilling the material.
So this is the machine in Fab Lab
we will fix the corners of wood sheet
we will fix a position for cutting
precautions There are emergency buttons you have to know them
this is wired to the machine system
and this one places on the right side of the machine
What are feeds and speeds?¶
Feeds : specifically refers to the feed rate the tool advances through the material basically speed of movement
Speeds : refers to the surface speed that the cutting edge of the tool is moving and is needed to calculate the spindle RPM. rpm= rates per minute (rotation)
For different speeds and feeds we expect different results. Big chips = high speed and vice versa. Also, sound is indicator of the speed of the machine. The Feeds and Speeds setting are calculated generally with calculators or internet charts.
Toolpaths¶
a series of coordinate locations that a cutting tool will follow in the machining process. They come in different shapes and sizes and each with its own product.
Sacrifice Sheets¶
wooden sheet that is placed under the sheet that will be drilled to support design during the process without damaging issues.
Securing the material¶
to fix a material you would secure the sheet with screws. In the tool path you would insert tabs for the screws
Softwares used¶
Some examples of softwares to use for CNC designs are Grasshopper, Rhino and Sketch chair.
Individual Assignment¶
My story begins hereee!!
First I chose a design which is kids play house!
Then I started to specify measurements, how it went? well first I searched about kid’s 3 years old standard length which is d 37.1 inches for girls and 37.5 inches for boys. Then I started to estimate the width of the cube that will be designed and here is the an image of the process and image of my measurements.
For design process I used Fusion360, Abdullah said my work at the beginning was ok all I have to do is to start constructing the parts in Fusion360 to build finger joints freely after this task. Here are four images of my failing tries.
Here I tried to construct the parts to start building joints¶
Here trying to build the windows¶
Here trying to build the doors¶
Personal issues and problems¶
1- Poor skill to combine shapes
The big problem I faced is combining the shapes was pretty challenging for me in Fusion360 I tried some tutorials but I always delayed this task so, Mohammed in Fab Lab helped me to combine the design. Also, I tried to follow along with tutorials in Youtube channel but procrastination caused many weeks of delaying this task until Abdullah did the whole process to be honest .
2- Unable to be patient
I referred to resources instructor Adullah recommendations but during the sessions of work I didn’t give it the real time to learn even though I had very very long time to learn.
So then I tried to construct a chair following this Youtube tutorial Click here!
but missed up again ;) chair missed up design as .fbx
CNC project is essentially about joints, Abdullah introduced us to many kinds of joints and we have to choose based on our design, some joints may make my design structure weaker and some joints will maintain the strength of my design structure.
Finger joint : finger joints requires designing sequence of equidistant square notches in first shape, Then cutting opposing notches in a second shape. This kind of joint is perfect for boxes. I chose this one because I found it common to be applied to my design.
Joints from Fablab¶
need to take photos from Fab Lab
resources¶
Fusion recommended videos Finger Joint
with help of instructor Abdullah, we generated the joints with length of 63.409 mm and width 11 mm, you assign these in user parameters so it makes your process easier and faster.
Length of the inner : 63.909 mm¶
Width : 11.00 mm¶
Length of the outer: 63.409 mm¶
we repeat the process for whole parts
other measurements
Vcarve¶
What is Vcarve? Vcarve is a software that allows you to do routing or engraving using standard tools to produce square-edged cuts of a set depth.
Toolpath section
Edit tool menue
fillets
in finger joints to let parts constructed like a box you have to choose t-fillet, this is one of the critical step in CNC to cut joints.
this kind of fillet to make internal parts appear clear
Heroshot¶
so not as expected due to my limitations with Fusion360, and my lack the ability of taking the right measurement although we could use it fot puppies !
Design File as .dxf(1) Design File as .dxf(2) Design File as .dxf(3) Design File as .dxf(4) Design File as .dxf(5)
Note¶
note that before joining fab academy I sticked to a goal that after completing Fab Academy weeks I’ll be hosting my own workplace, and as shown CNC design is one of my big weaknesses so, I joined volunteering team that will conduct different projects to learn and gain skills more !