Frequently Asked Questions
What temperatures and duration does the laminate need to withstand in order to survive lead free processing?
Before placing a printed circuit board order, buyers should know the maximum temperature and maximum time their assembly process requires. This information will depend on your solder process and your lead free alloy processing temperature. The time is accumulative, so if you wave solder a part for 5 seconds, reflow it for 8 seconds and then rework it for another 5 seconds you will have a total of an 18 second excursion. Temperature thresholds typically being referenced are T-260 and T-288 ratings. These are thetimes it would take for a sample to delaminate at either 260° or 288° C constant temperature.
What are the Dielectric and Impedance values of the printed circuit board design?
Boards designed for specific dielectric attributes of most FR4 laminates may not function correctly when placed on higher thermal capacity materials. It is important to understand the function of the board and that a laminate or a final finish change could alter the designer’s intent. As an example, a typical mid range Tg laminate has a Dk of 4.25 at 1GHz while a high temp material from the same manufacturer is at 4.6. The Df ranges from 0.016 to 0.023 on the higher thermal capacity material. If you have questions about the direction to go, consultation with the designer is a must.
Is there a special marking on the boards that would indicate RoHS compliance?
We will not be using any lead-free symbols on the bare boards. Both IPC and JEDEC standards for marking, symbols and labels for identification of lead free assemblies, components and devices do not call for board level markings. However, you will see the Lead-Free label on the packed PCB stacks.
Q: What are the most common reasons why an order may get on hold?
1. A Gerber file or Aperture file is corrupt or missing from Gerber Package.
2. No board outline provided.
3. Missing drill file or drill size.
4. Missing holes.
5. Plated and Non-Plated holes are not clearly defined.
6. Isolated thermals pads on Negative Polarity Layers.
7. Dimensional differences between Gerber and fabrication print.
8. Gerber files are not 1:1 (true size).
9. Layer stack-up (construction) and order of the layers is not defined.
10. Final board thickness is not defined.
11. Cu foil thickness is not defined.
12. Material type is not defined.
13. Surface finish is not defined.
14. Component PTH holes or SMD pads covered with Solder Mask.
15. Readable / Not readable text in same Print Layer.
16. Layers drawn only with surfaces (no pads and lines).
17. More than 1 circuit board design exists on the image. (Please include only one circuit board design per order. Our engineers carefully evaluate the gerber files to make sure that multiple part numbers are not included. We reserve the right to refuse jobs that do not fit our criteria).
Q: What files do I need to include?
The following critical problems are those that cannot be resolved without customer involvement. Customer involvement and contact is generally conducted via faxes, direct meetings and e-mail. Table below presents the minimum files and information that is required to create fabrication tooling.
- Missing PCB artwork file(s)
- Missing fabrication drawing/file(s)
- Missing README file (including PCB information and special instructions)
- Missing aperture information/file
- Missing netlist, when a netlist test is required
- Drill file(s) and layer connectivity (blind and buried via layer combinations) not specified
- Sender not identified
- Bad or unknown compression
PCB Data in Gerber files (274X or 274 with Apertures list) or ODB++ format and named with extension:
.plt (silktop), .smt (solder mask top), .top (top), .in* (where * is Inner Layers No), .bot (bottom), .smb (solder mask bottom), .plb (silkbottom), .out (outline), .mil (additional routing), .sco (scoring), .gtp (pastetop), .gbp (pastebottom).
• Drill file in Excellon, Sieb&Meyer or 274X named:
.pth (plated holes),
.npth (not plated holes).
• Fabrication Print in Gerber format, showing the board outline with drill pattern and sizes.
• ASCII text file named Readme.txt with specification details for the PCB, including thickness and surface finish.
• Text file with complete set of contact information where you can be reached (Your Name, Company Name, E-mail) where we should send information for technical questions regarding your design.
Q: What are our suggestions for your design?
• Drill files to be in Gerber 274x format.
• If the drill file is in ASCII format, drill size to be applied in the header of drill file.
• Drill files for pth and npth holes to be separate.
• Via holes to be define in drill file.
• Pth slots to be in separate layer.
• Surfaces not to be used in Copper Layers or Print Layers (minimum line for fill 100mic).
• Text, PCB name or Logo to be draw with minimum 100mic lines (get out of pads).
• All pads to be constructed (not drawn with lines).
• Copper Layers should be without contour lines.
• Net surface to be drawn with minimum 200mic/200mic lines/space.
• Slivers and Pinholes to be minimum 150mic.
• Minimum space between smd pitch on Copper Layer to be 150mic.
• Thermal Air Gap on Negative Inner Layers minimum 200mic.
• Same net spacing on Positive Layers minimum 150mic.
• Avoid sharp surface edges.
You will be sent an e-mail if your job goes on hold.
Q: What if I need to cancel my order?
Call our sales representative immediately if you need to cancel an order and follow up with a fax or email to confirm. Orders already in process are subject to a cancellation fee. Please ask your sales contact for details.
Q: Where should I send the gerber files when placing an order?
Final version of Gerber files is necessary at the time of order and you may send the files to the email email@example.com together with your Purchase order.
Q: What happens if freight couriers are late in delivering my order?
There are occasions when the freight carriers have delays and/or make shipment errors. We regret when this happens but we cannot be responsible for delays by these carriers.
Q: How do you define your turntimes?
The day when the order is placed/confirmed to the customer is counted as Day 0. One-day express orders, for example, ship the next business day.
Delivery days counting example:
Order placed at Feb 1st for delivery 3 working days.
Feb 1 (13:00h) to Feb 2 (13:00h) = 24h
Feb 2 (13:00h) to Feb 3 (13:00h) = 24h
Feb 3 (13:00h) to Feb 4 (10:00h) = 21h
3 working days in production
Delivery date from Hi-Tech Corp.will be Feb 4th. Add 24h for parcel shipping with freight couriers.
Q: Does your company ever have any leftover stock from previous orders?
Prototypes stock is kept for approximately six months. Please call your salesperson for availability.
Q: If I only have a minor change in my design, do you charge Tooling /NRE?
Depends from the changes you have made in the design. Even a minor change will require the same process as new files, so a tooling charge apply. Please contact our sales person for details.
Q: What do you need if I want my pcb panelized in array format?
We recommend you send us your complete array pre-panelized. This allows you to set up the array exactly the way you want it. If you need us to set up your array, please be aware that additional engineering time will be billed per order.
Q: Are you UL "Underwriters Laboratory" approved?
Yes, you can access our UL Registration
Q: Are you MIL SPEC approved?
No. However, you can order prototypes with us because we apply the same tolerances and use the same materials, specifications, and processes.
Q: To what acceptability standards to you build?
IPC-A-600 latest revision: Class 3 (Prototypes) and Class 3 (Production).
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