CNC-Machining a Connector-bar To demonstrate the complexity involved in CNC-machining parts in-house, this presentation follows the step-by-step manufacturing of YG Acoustics’ most frequently-produced parts. Machined connector-bars are used inside all YG Acoustics speakers to fasten two enclosure-panels together at any desired angle, in substantial quantities of anywhere from 100 to a whopping 648 connector-bars per pair of speakers. The photo below shows a typical YG Acoustics speaker’s inner structure. The connector-bars are marked in yellow.

Step 1 – feeding raw material into machine A bar of raw aircraft-grade aluminum is automatically fed, piece-by-piece, into YG Acoustics’ 5-axis CNC MillTurn. Example 1:

Example 2:

Step 2 – verifying raw material dimensions Raw material is typically not of a very precise size. Therefore, the first stage of YG Acoustics’ accurate machining process is to very slightly trim the raw material, so that its size becomes exactly what the machining-program expects. In the two connector-bars below, this trimming involves a slight reduction of the length and the circumference. Example 1:

Example 2:

Step 3 – long parts require stabilization For long parts only, a central hole is drilled. Then, a massive hydraulic support known as a “tailstock” grips the part’s end through the hole to increase stability during subsequent machining. Central hole:

Tailstock in position (on right) stabilizing the part:

A custom cutting tool for trimming the length, circumference and drilling the tailstock-hole, all in a single CNC operation:

Step 4 – from round to square or rhombic The round bar is CNC-milled from all 4 sides, to give it a square (90 degrees) or rhombic (any desired angle) cross-section. This operation is one of YG Acoustics’ key advantages: any angle can be generated with very high precision, thus allowing for non-parallel internal speaker-walls, which in turn avoids standing-waves and resonances. In comparison, the competition is mostly limited to standard extruded square cross-sections, which do not allow for any desired angle, and suffer from looser tolerances. Rhombic example:

Square example. Note the accuracy – 15.00 mm, down to the hundredth of a millimeter (a hundredth of a millimeter is less than half a thousandth of an inch)!

Step 5 – screw holes Holes are drilled, and screw-threads are milled inside them, to allow for enclosure-panels to be fastened tightly, and precisely at the desired angle. An example with off-center screw holes at non-90-degree angles:

An example with both screw-threaded and smooth-bore holes:

Step 6 – cutoff The CNC-machined connector-bar is separated from the remaining bar of raw aircraft-grade aluminum, automatically picked up by a mechanical arm, and removed from the machine. A cutoff tool separates the machined part (right) from the raw material (left)

The cutoff is complete, the part landed inside the mechanical arm.

Step 7 – part is ready, inspection can begin The connector-bar is fully machined, and ready for the next step in the process: a stringent quality-control inspection. A fully CNC-machined connector-bar

The non-90-degree angle of YG Acoustics’ rhombic connector-bars is clearly visible when viewed from the ends.