Identifying metal for plating

• The Sixty-Eight Mixer has many metal parts, and five that needed gold plating. Parts were selected from our inventory and verified to be perfect in every aspect. Fortunately these parts were relatively easy to select as all Rane components, electrical and mechanical, undergo rigorous inspection before they are ever inventoried.

Removal of paint

• All Rane metal parts used in its DJ mixers are fabricated from special steel coated with an alloy of zinc and aluminum. This metal is specified because it will not rust and complies with all existing environmental regulations throughout the world. For the Sixty-Eight mixer these parts are also painted. The painting process is a powder coat process ensuring all surfaces are painted evenly and baked on. This produces the most durable finish available today. However, the gold plating cannot be applied on painted parts so this paint has to be removed. Using potent chemicals the paint was stripped and the parts made ready for plating. Rane’s President and CEO did the paint stripping (“I don’t want anyone else handling these chemicals,” he said). Rane is small, and even the CEO has to occasionally work.

Part Inspection

• Once the paint was removed, the parts were carefully inspected for imperfections. First by the CEO, and then by others who knew how to “properly” examine the parts.

Verification of fit and dimensions

• Gold plating is expensive. To reduce the likelihood of unforeseen problems, the mixer was fully assembled in the metal. All parts were again verified to fit perfectly. The mixer was then disassembled and the metal prepared for plating.

Preparation for Gold Physical Vapor Deposition Plating (PVD)

• Rane has a very complete manufacturing facility but cannot do gold plating. Gold plating companies are specialized and unique. We made arrangements with an East Coast company specializing in finishes for jewelry, high-end automotive and aircraft manufactures to apply a PVD finish to the Sixty-Eight metal.
• Prior to the plating process, the parts were carefully prepared by inserting all the various fasteners into threaded holes to keep the plating process from clogging the threads, and documenting the surfaces to be polished and plated. Then they were packaged with loving care and sent to the plating company.

Selecting electronic components for assembly

• The gold Sixty-Eight is crafted as a special single unit. The first step is to collect the necessary parts. This is done in the Rane storeroom and these parts are brought to the manufacturing floor where they are staged along with other parts already loaded onto various pieces of automated equipment that does much of the assembly.

Circuit board preparation

• The “raw” or “bare” printed circuit boards (PCB) are the backbone of the electronic circuitry of the Sixty-Eight mixer.  Common with all of Rane’s high quality circuit boards, the solder pads are gold plated for reliable electrical connections. The first step is an inspection to verify the integrity and physical properties of the boards. Then a small amount of preparation (“prep”) work is done, primarily applying a heat resistant Kapton® tape to selected solder pads.

Screen printing of solder paste

• A solder paste is applied to pads on the circuit boards. What may seem a simple process is actually very complex. The paste alloy and mixture must be perfect, while the temperature and on-screen consistency of the normally refrigerated paste must be controlled. The screen print stencil mask must be precise to 0.002” and the mask registration to the circuit board must be within 0.001” on both the x-and y-coordinates.

Pick and place of components

• Once the solder paste is in place, the various electrical components are placed on the PCB. This is accomplished by a very precise “Pick & Place” automated assembly machine. Rane has several of these machines, and to keep them “in tune,” a dedicated technical support staff.  These machines take the very small surface mount technology (SMT) parts and places them on the circuit board with their respective conductors immersed in the solder paste. Precision is everything. Each part has to be exactly placed -- no small task when you are dealing with parts as small as 0.063” x 0.031”. The Sixty-Eight has about 1,500 individual parts that must be placed on its various circuit boards. The technology and some of the components are equivalent to that used in the latest personal computers.

Reflow soldering

• Once “populated” with the components, the circuit boards are processed through the reflow oven. This machine is similar to a very precise and expensive pizza oven. The boards are placed on a motorized conveyor belt that brings the board into the oven where it is progressively heated through seven different zones to a point where the solder paste liquefies. As the belt moves, the board is then progressively cooled until the solder hardens, securely attaching the components to the board circuitry. The precision required during this operation to heat and cool the board and the components profoundly affects the reliability and performance of the final mixer. The heating and cooling profiles are scientifically determined and closely monitored -- they must be perfect.   

Automated optical inspection

• It would be almost impossible and certainly impractical for an individual to manually inspect the assembled circuit board and verify that every part was precisely in place and properly soldered. This task is left to automated optical inspection equipment. In a matter of minutes this machine optically inspects the PCB assembly and verifies that the correct components are installed at the correct locations and the solder joints conform to the highest standards.

Radial Insertion

• Not all parts are SMT parts. Some are called “radial” components, with leads on one end of the part that go through holes in the PCB. These components tend to be special precision capacitors and indicating light emitting diodes. They are now inserted and the leads cut and clinched on the bottom side of the circuit board by a rather large automated insertion machine.

Hand insertion

• Humans are important! Especially at Rane. Not all components can be assembled onto the circuit boards by machines. Some components must be placed by hand. Mixers have quite a few of these types of components typically associated with the input and outputs that interface the mixer with other signal processing elements. Over the years Rane has spent countless hours searching for the best components to use in this interface. We spare no expense here. Only top-of-the-line components are used.

Wave soldering

• The radial and hand inserted components now need to be soldered. This is accomplished using wave solder equipment. The components’ leads penetrate the bottom side of the circuit board and this side is drawn over a standing wave of molten solder. The solder then solidifies and affixes the component to the circuit board pads. This too is a technical process requiring careful monitoring of time and temperatures.

Final component placement and inspection

• The circuit board assemblies are almost complete. But first a few final components are attached to the circuit board by hand soldering. These are mostly temperature sensitive components, or mechanically awkward things like metal brackets and various wires. All bottom side solder joints are inspected. Then the PCB assemblies are routed to the Test department.

Electrical performance verification

• The final phase of circuit board assembly is the electrical verification of performance. This is accomplished using special test fixtures and computer controlled test equipment that test EVERY performance parameter. This kind of testing is unique to Rane. Most companies test only a few key parameters and from those assume the rest are within limits. Rane, as a policy, has never done this. We test EVERYTHING. Our test engineers work closely with our design engineers to determine what EVERYTHING is and that is no simple task. It would be nice to claim that this gold Sixty-Eight gets special scrutiny because it is unique. But in truth it gets the same level of in-depth testing and verification as all Rane equipment. After testing, the boards are set aside to await final assembly into the gold metal casing.

Silk-screening

• The gold plated parts have returned from the plater! They look gorgeous. We now have to silk-screen the parts with labels and logos. We have learned that by screening parts in-house we have the best control of these important metal features. Our facilities include a darkroom to produce images on screens and a screening room with benches and drying cabinets. Our experienced screeners take extra special care to align the screen image to the metal before applying ink. Four of the five gold plated metal parts require screening, with the top needing three separate passes for the different colors.

Kit pulling of final parts

• Rane’s Production and Inventory Control department has been monitoring the progress of the circuit board assemblies and metal parts, and when they are complete issues a work order that provides all the parts required to assemble the final gold unit. Rane storeroom personnel gather the necessary parts, place those parts on a cart and deliver it to the final assembly area. For this special gold mixer this gets a lot of attention. All manufacturing personnel are excited about seeing this gold unit complete.

Mechanical assembly

• All the pieces come together in final assembly. The assembly is a lengthy process, typically taking one and three quarters hours to complete. Not only do all the nuts, bolts, wires, circuit board assemblies, and controls have to be in place but the fit needs to be perfect. Assemblers have to ensure that the knobs are free but tight on the shafts, the nuts torqued to the proper specification, and electrical ground paths and shielding are intact and working. The process instructions for the Sixty-Eight mixer are over 20 pages of details. This is hand crafting a musical instrument equivalent to any guitar or violin made today.

Magnetic fader assembly

• Rane’s patented magnetic fader is the standard by which all other non-contact faders in the industry are measured. These are hand-built one at a time and individually calibrated for each mixer location to be absolutely precise in tracking. This precision is found in all Rane mixers and is unique in the industry.

Final complete unit testing and performance verification

• Testing of the Sixty-Eight Mixer is a thorough and lengthy process. The electrical test is accomplished by a custom computer-controlled test fixture. All parameters are verified to be within original design specifications. Fader tracking must be perfect tone controls must be precise. On these two controls alone more than 200 separate tests are performed. Rane does not sample test and then rely on statistics to infer that the mixer is performing to specifications. EVERYTHING is tested.

Test results

• Test results are reviewed by the test technicians, and only when they are perfect is the unit sent on for final inspection and packaging.

Final inspection

• The last inspection is performed at our listening benches. First the mixer is given a visual verification for proper fit and finish. Then the mixer is connected to a music source and using headphones our inspectors become DJs. All controls are turned and switches activated to ensure they operate correctly and have the desired “feel” and nothing has been overlooked.

Packaging

• The very last step is the proper packing of the unit for shipment. What would seem a pretty simple task has many elements and requires attention to detail. This is where the various regulatory agency labeling must be accounted for. Serial numbers must be verified and recorded (the Gold Sixty-Eight Mixer has Rane serial number 796904). Even the corrugated box and the packaging material are the result of a long design and certification process. We print the operator's manual just as the unit is completed to ensure it has the most recent updates and accuracy. The list of accessory items included with the mixer is extensive; Serato® Scratch Live™ software CD, vinyl records, control CDs, line cord and USB cables. The packagers ensure everything is there and correct before sealing the box.