What are design rules?
Design rules are a set of geometric requirements that are applied to candidates to ensure that the candidates that Quilter generates are manufacturable and electrically complete.
We call the application of design rules a "Design Rule Check (DRC)" – they're extremely important and natively supported in all popular PCB design tools, including Altium and KiCAD.
Quilter packages the following set of fabrication design rules in design rule "profiles" that are utilized to explore the viability and performance of various layout candidates:
Minimum trace width
Minimum trace clearance
Minimum drill hole size
Minimum annular ring size
Minimum edge-to-copper clearance
How does Quilter use design rules?
Quilter uses design rules in two important ways:
1/ To explore the possibility space for your design
When Quilter starts a layout job, it commissions a range of candidates by starting with a variety of stack-ups from different fabricators and applying a range of minimum design profiles that span from very aggressive (as small as 3 mil trace widths) to more conservative (as large as 10 mil trace widths).
This gives Quilter the opportunity to understand the design rule set that will achieve the best balance of completeness, manufacturability, and performance for your specific design.
Complete candidates that satisfy all physics rule checks (PRCs) with the most conservative design rules are automatically recommended for selection as a part of the candidate review process.
2/ To ensure that candidates are free of design issues
By defining design rules against the minimum fabrication specifications for each of our fabricator partners, Quilter also ensures that each candidate that we generate can be successfully manufactured by that fabrication partner.
Design rule checks are performed throughout the candidate generation process by Quilter's DRC engine. A final ECAD-native DRC check is also performed on each complete candidate before it is delivered to the Candidate Reviewer for final selection.
How does Quilter decide what design rules to use?
Quilter's design rules have been defined in partnership with top fabricators and can be bucketed into a few different groups:
"Minimum" design rule profiles
These design rule profiles are defined against our partners' minimum fabrication capabilities. They are usually only available with boards with larger layer counts and often come with higher costs and longer lead times.
Example: Oshpark (5 mil traces), JLCPCB (3.5 mil traces), MacroFab (3 mil traces)
"Standard" design rule profiles
These design rule profiles are defined against minimum fabrication capabilities for "standard"-level services. They are more conservative and typically support lower cost, quick-turn fabrication services and boards with fewer layers.
Example: Oshpark (6 mil traces), JLCPCB (5 mil traces), MacroFab (5 mil traces)
"Common" design rule profiles
For most designs, you want to avoid designing against minimum requirements. These design rules are comfortably supported by all our fabrication partners. Quilter will always recommend candidates with the most conservative design rules that are also 100% complete and contain 0 DRC or PRC (physics rule check) violations.
Example: 8 and 10 mil trace widths/clearances
What design rule profiles does Quilter use?
Quilter generates layout candidates by applying the following design rule profiles to a corresponding list of compatible stack-ups.
Note: Quilter frequently adds new stack-ups and design rules to its system, so this list is not guaranteed to be exhaustive or up-to-date.
Rule name | Profile type | Min trace width | Min copper clearance | Min ring size | Min drill size | Min edge clearance |
Oshpark_2_Layer | Standard | 6 mil | 6 mil | 5 mil | 10 mil | 15 mil |
Oshpark_4_Layer | Aggressive | 5 mil | 5 mil | 4 mil | 10 mil | 15 mil |
Oshpark_6_Layer | Aggressive | 5 mil | 5 mil | 4 mil | 8 mil | 15 mil |
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JLCPCB_2_Layer | Standard | 5 mil | 5 mil | 0.3 mm | 0.3 mm | 0.3 mm |
JLCPCB_4_6_Layer | Aggressive | 3.5 mil | 3.5 mil | 0.3 mm | 0.3 mm | 0.3 mm |
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MacroFab_Std_1oz | Standard | 5 mil | 5 mil | 4 mil | 10 mil | 10 mil |
MacroFab_Ext_Mfg | Aggressive | 3 mil | 3 mil | 3 mil | 10 mil | 3 mil |
MacroFab_Ext_Drill | Aggressive | 5 mil | 5 mil | 4 mil | 4 mil | mil |
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CircuitHub_Std | Standard | 6 mil | 6 mil | 6 mil | 12 mil | 12 mil |
CircuitHub_Adv | Aggressive | 3 mil | 3 mil | 4 mil | 6 mil | 8 mil |
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Common_6_mil | Conservative | 6 mil | 6 mil | 6 mil | 12 mil | 20 mil |
Common_8_mil | Conservative | 8 mil | 8 mil | 6 mil | 12 mil | 20 mil |
Common_10_mil | Conservative | 10 mil | 10 mil | 6 mil | 12 mil | 20 mil |
FAQs
Can I choose which design rules Quilter uses to generate my designs?
While you can't currently prevent Quilter from exploring candidates with particular stack-ups or design rule profiles, you can easily filter for candidates that utilize your preferred design rules using the global candidate filters at the top of the Candidate Review page.
More details on that here.
Can I define or upload custom design rulesets?
Not at the moment, though it's something we plan to add to the product shortly. In the meantime, send us a note via the chat box at the bottom right-hand side of our site, and we'll see if we can get it added to the application for you.