Doug Griffith
02-07-2012, 9:28 PM
I thought I'd share another doohicky I built on the laser. This time I raised my hand to build a plastic bender. It accepts a vacuum formed part and folds each side up 90 degrees.
This pic shows the CAD file of the bender. It was built with layers of .216" MDF in mind from the get go. Once I sourced the components and downloaded their CAD files from McMaster Carr, I used their geometry to drive the design of the bender. This took me about 8 hours.
223051
To get the 3D layers to 2D artwork, I laid all the wood parts flat and then converted them to surfaces. From there, I sent the topmost surface of each part to a layer and converted to curves. From there I exported the curves to Illustrator and did some manual nesting. The top grouping was cut once. The bottom twice.
223052
Here are all the parts after cutting. It took just under 60 minutes. A few aluminum pieces were saw cut from a single T-shaped extrusion.
223053
This is one of the "wings" that slides in and out to clear the heating elements. A layer of laser cut card stock that was used to give clearance for sliding. After the corners were "beburred", it slid freely.
223054
This piece sandwiches the toggle clamp and is used to hold down the plastic during forming. Once everything is adjusted, it will be bonded together. It was also coated with many layers of varnish which makes it more durable. There is a negative angle of 3 degrees on each side to allow for plastic spring back.
223055
Here is the assembled unit in the loading position. The hold down is not installed yet. Short drawer glides are used to position each "wing".
223056
Here it is in the heating position. Nichrome wire, ceramic insulators, and a variac are used to do the heating.
223057
Here it is in a partially folded position. The openings at the bottom of the picture interfere with the drawer glides unless the wings are at the bend position. This is to prevent folding the wings up while the plastic is in between the heating wires. That would be bad.
223058
The whole unit took less than 3 days to create which is far less than if it was to be CNC machined. It was actually my entertainment during Super Bowl Sunday.
This pic shows the CAD file of the bender. It was built with layers of .216" MDF in mind from the get go. Once I sourced the components and downloaded their CAD files from McMaster Carr, I used their geometry to drive the design of the bender. This took me about 8 hours.
223051
To get the 3D layers to 2D artwork, I laid all the wood parts flat and then converted them to surfaces. From there, I sent the topmost surface of each part to a layer and converted to curves. From there I exported the curves to Illustrator and did some manual nesting. The top grouping was cut once. The bottom twice.
223052
Here are all the parts after cutting. It took just under 60 minutes. A few aluminum pieces were saw cut from a single T-shaped extrusion.
223053
This is one of the "wings" that slides in and out to clear the heating elements. A layer of laser cut card stock that was used to give clearance for sliding. After the corners were "beburred", it slid freely.
223054
This piece sandwiches the toggle clamp and is used to hold down the plastic during forming. Once everything is adjusted, it will be bonded together. It was also coated with many layers of varnish which makes it more durable. There is a negative angle of 3 degrees on each side to allow for plastic spring back.
223055
Here is the assembled unit in the loading position. The hold down is not installed yet. Short drawer glides are used to position each "wing".
223056
Here it is in the heating position. Nichrome wire, ceramic insulators, and a variac are used to do the heating.
223057
Here it is in a partially folded position. The openings at the bottom of the picture interfere with the drawer glides unless the wings are at the bend position. This is to prevent folding the wings up while the plastic is in between the heating wires. That would be bad.
223058
The whole unit took less than 3 days to create which is far less than if it was to be CNC machined. It was actually my entertainment during Super Bowl Sunday.