PCB Assembly FAQ

Technical Assembly and Capabilities FAQs

1. Do you offer RoHS-compliant assemblies?
   Yes. We do offer RoHS-compliant assemblies.

2. Do you offer testing and inspection services?
   Yes. We do offer different types of testing and inspection services.

3. What are the different testing services provided by you?
   All the PCBs undergo testing and inspection in every phase of assembly. The PCB assemblies are subjected to the following types of testing:
   • X-ray Testing: This testing is performed as a part of the standard assembly process on Ball Grid Arrays (BGAs), Quad-flat-No-lead (QFN) PCBs and more.
   • Functional Testing: In this, we perform the functionality check on the PCB. This is performed to ascertain if the PCB is working according to the requirements specified by the client.
   • In-Circuit Testing: As the name suggests, this testing is performed to check the joint failures or shorts.

4. What are the different assembly inspection services provided by Sierra Assembly?
   We conduct an in-depth inspection of components and their functioning on the assembled PCB. They are subjected to Automated Optical Inspection (AOI). This helps identify, polarity, solder paste, 0201 components, and if any components are missing.

5. What standards and certifications does Sierra Assembly follow?
   At Sierra Assembly, the PCB assemblies adhere to the following standards and certifications:
   • ISO 9001:2015+ AS9100D Certified
   • IPC J-STD-001 Compliance

Turnkey Assembly FAQs

1. What is a turnkey order?
   Turnkey is a term for the service where you have to provide us documentation or files, and we will build the PCB from scratch by selecting the board level components, materials, and the SMT stencil. We will return the assembled PCBs to you.
    
   At Sierra Assembly, we provide the following types of turnkey assembly services:
   • Full Turnkey: In this type, the entire assembly process is handled by our experts. We order all the parts including circuit boards and components for you, as well as conduct assembly, testing, and inspection before shipping the product to your address.
   • Partial Turnkey: In this type of assembly, we ask clients to provide all the required circuit boards, components, and we help with the assembly, inspection and testing, and shipment of the assembled circuit boards.

2. What documentation or files are required for a turnkey assembly?
   • Your Gerber files including top and bottom silkscreen, solder paste layers, and copperAd
   • The Centroid data file featuring rotations, component locations, and reference designators
   • BOM (.xls) with vendor’s names, quantity, reference designators, part and package descriptions, and quantity
   • Types of components including SMT, thru-hole, fine pitch, BGA, and more
   • Any additional instructions and requirements

3. What is the lead time for a turnkey order?
   Assembly lead times quoted to the client exclude the procurement lead time. The lead times for the turnkey order entirely depend on the time required to source the part. The assembly begins only after all the components are available in the inventory.  

4. What happens to the leftover or unused components on turnkey orders?
   The components that have limited uses are returned to the customer along with assembled circuit boards. However, other components are retained in our inventory.

5. What is the minimum order requirement for turnkey PCB assemblies?
   There are no minimum order requirements. However, we always inform our clients that larger orders will help them save more money. If you discuss your requirements and budget with our experts, we can help you find the right solution according to your needs.

6. Do you offer any assistance in part crossing and substitutions?
   At Sierra Assembly, we conduct a detailed check on your Bill of Material (BOM) and share the list of components that are already available with us. Most of the times, these components are free parts or low price parts. In addition to this, our experts will also help you reduce the cost of manufacturing by utilizing our free cost parts. The final decision always lies with you.

7. What is the turnkey assembly process followed at Sierra Assembly?
   A turnkey assembly process at Sierra Assembly proceeds in the following ways:
   • The order and order details are confirmed by the experts.
   • The board level components and the circuit boards are ordered by us.
   • We order and receive the SMT paste stencil.
   • Our experts will program the machines from centroid file and the BOM, before receiving the materials.
   • The materials are checked for their quality, and audited before starting the assembly process.
   • If the materials are received in the first half of the day, the assembly will start soon. If they arrive in the second half then the assembly will start the next day.
   • The paste is applied on the component using a stencil printer or the SMT stencil.
   • The SMT components are placed using an automatic pick and place machine.
   • A reflow oven is used to reflow the solder on the SMT components.
   • Solder bridges or other inaccuracies are avoided by X-raying BGA components.
   • Thru-hole parts are hand inserted or wave soldered on the circuit board depending on the application requirement.
   • A quality check is performed by the experts.
   • PCBs and all the leftover materials are shipped to the customer.

Assembly File and Kit Requirements

1. What is a Centroid Data?
   Centroid data, also referred by names such as pick-and-place data, insertion data, or XY data, is the machine file comprising information such as Theta, X, Y, Reference Designator, or Side of Board (Bottom or Top).

2. Can you generate a Centroid file for me?
   Yes. We can generate a Centroid file from the Gerber file provided by you.

3. How can I provide components for the assembly?
   You can provide the components in a tray or bag that is clearly marked with the part numbers from your BOM. Please take care to protect the components during the transit. You can contact our experts to understand how the components can be supplied.

4. How can I ship parts and components for kitted/consigned orders to Sierra Assembly?
   Please ensure that all parts and components are included as per the BOM line item number or the manufacturer’s part number or customer part number. The package containing these parts and components must be neatly marked with the order number, inventory list of components, and their quantity, and addressed to:
   Attn: (Order Number)
   14764 Yorba Court
   Chino, CA 91710

5. Can I place multiple orders at the same time?
   Yes. You can place multiple orders at the same time.

6. How should I submit the parts for multiple orders?
   As discussed before, each order must be neatly packaged with its all required components. If you are sending mutual parts for both the circuit boards, please ensure to provide 5% extra parts for each assembly. These parts must be clearly marked with a sticker denoting the ones that are common for both builds.

7. Do you offer aftersales support on assemblies?
   Yes. We do offer aftersales support on all PCB assemblies. If there is an issue in our workmanship, our experts will evaluate them and repair, remake, or rework on them by determining the root cause of the problem. For any assistance, please contact us on 909-606-7700, and we will issue an RMA number.