Vacuum Pick Up


Overview and G-Codes


Vac foot installed on router.
Vac foot on router.
This vacuum assembly is made for the 18x24 machine, but it will work with others.

The wooden pieces, the foot and cradles, are CNC cut from ¾ inch stock. The g-codes are linked at the bottom of this section.

A 1-½ inch sink tail piece is tied to the router with a #56 band clamp and a pair of cradle-brackets.

A short section of pipe is pressed into the wooden foot. Its end can be notched to match the inside shape of the foot. The pipe can be held in place with glue or pins.

This section of pipe is inserted in the receptacle end of the sink tail piece.

A small screw holds the foot in place. This permits the unit to be removed easily for bit access.
 
Vac foot - drink bottle.
Brush cut from bottle.
The foot is sized to use a ring cut from a plastic 2 liter soft drink bottle as the brush assembly.

The plastic ring is slid around the foot; the fit is tight. Bristles are then cut in the plastic with scissors.

The width of the bristles can vary. Cutting the bristles will probably cause the plastic to curve inward as shown.

Clear plastic allows the router bit to be viewed.
 
The experience here has been that vac feet are awkward to use, and the brush bristles are never the right length. Long ones are cut by the router bit, and short ones allow too much blow-by.
The drink bottle system addresses this by making the bristles simple and inexpensive to replace.
Extra feet with different length bristles for different jobs and router bits can easily be fabricated.
 
Foot CNC cut from plywood
Vacuum pick-up foot.
These codes are for ¼ inch straight bits.

Z zero is the top of the ¾ inch stock. X zero, Y zero is the lower left hand corner. The bottom of the cut is −0.8 inch (negative 0.8 inch). A spoil board under the stock protects the table top.

The finished foot is ~5/8 inch thick. Thinner stock can be used, and the first few passes will cut air. Take care that Z zero is ¾ inch above the table bed or the bit will cut deeply into the bed.
 
Vacuum cradle
Vacuum cradle.
The same directions for the foot apply to the cradle-brackets, except the brackets are the same thickness as the stock.

A slice can be cut in the cradles between the hole and the arc, as shown here, should the fit of the tail piece be too tight.

MDF and quality plywood work for these vacuum components.
 
The codes have been simplified to only use G01 moves. All arc and circular motion is broken into short line segments. This is done so the codes can be used with basic controller software.

These short segments will cut more smoothly with constant contour activated. (G64 in Mach)
The first three lines of the code may need to be deleted with TurboCNC.

Disclaimer: These codes have been tested on my CNC systems and have worked well.

You assume all risk and responsibility when using them.
 
G-Codes           Vac Foot      Vac Cradle
 
Foot CNC cut.
Vacuum pick-up.
Here is another system that has worked well with an older CNC machine. The problem is it took a lot of time to make, which prompted the design of the above drink-bottle system. These vac feet will be dinged with use.

First measurements were made and drawn in Rhino 3D with toolpaths created in RhinoCAM.

The part was CNC routed, then sawn from the block, glued together, used as a mold for fiberglass, and finally assembled and installed.
 
Draw in Rhino
Drawn in Rhino.
Foot CNC cut from plywood
Toolpaths created.

Carved with CNC router.
CNC carved.


Halves glued together
Glued together.
Covered with fiberglass
Covered with fiberglass.
The parts were then assembled and painted.

The brush assembly is a snap ring made from PVC pipe that has paint brush bristles hot glued to it.

In the above image of the completed unit, the black knob at the junction of the gray offset and white pipe loosens to permit the entire assembly to be removed for bit changes.
 
Hose from ceiling
Hose swivels from ceiling.
The vacuum hose over our 4x8 table swivels from the ceiling.

Parts are standard DWV (Drain Waste Vent) plumbing fittings and vacuum hose.

A metal elbow section of plumbing pipe swivels in the DWV pipe connection on the ceiling. This is the same plumbing fitting as is used underneath many kitchen sinks. The locking nut is left loose so the elbow can move with the hose.

These 1-½ inch plumbing fittings fit well inside 1-½ inch vacuum hoses. These are the thin walled fittings used in exposed areas such as inside bath and kitchen cabinets.
 

Vacuum cyclone.
Cyclone and mud bucket.
The vac is powered by an abandoned run-of-the-mill vacuum cleaner motor, and is vented outside.

The table does not always require a great deal of suction, so a speed control dials down the vac's velocity and noise level.

The unit never loses suction due to a dirty bag since the cyclonic separator makes a filter unnecessary. Jetsam is caught in the mud bucket at the base of the cone.

The shape of the cyclone can be within a large range when the vac is vented outside.

In this setup the cyclone's purpose is to remove the dust that could damage the impeller, not to remove all particles that are harmful to lungs.

The inlet tube to the cyclone is a sweep elbow inside the cone. This directs the chips in the direction of the vortex.

It is better for this entry leg to be long to allow the chips to gather momentum so they will tend to sling around the sides of the cyclone and thus be better separated.

Again, since this unit is vented outside, high efficiency is not required and the sweep elbow serves well enough.