The short answer
On pocketed plates and housings, the **corner radius** in the 2D pocket outline is not the same note as the **floor fillet** where the wall meets the pocket bottom. Corner R should be at least as large as the finishing tool you are willing to pay for; leftover CAD radii of R0.2 or “sharp as modeled” force tiny tools or rest-machining passes. Silence on **minimum corner R**, **whether a sharp internal corner is truly required**, and **how the floor fillet differs** is what widens many [quote-new.php](https://3dwk.com/quote-new.php) **rates.v1.1** estimate bands—not pocket volume alone.
This guide is for buyers packaging 7075 automation plates where deep pockets look sharp in STEP files exported from a solid that was never reviewed for cutter diameter. Illustrations use an **Example part** only—not a customer automation nest. Sibling notes live in [CNC pockets, thin walls and undercuts](https://3dwk.com/resources/cnc-pockets-thin-walls-undercuts), [fillet vs sharp internal corners on CNC RFQs](https://3dwk.com/resources/fillet-vs-sharp-internal-corners-cnc-rfq) and [sharp internal corners and CNC quotes](https://3dwk.com/resources/sharp-internal-corners-cnc-quotes); here we focus on **pocket corner-R DFM** so estimators do not guess a 1 mm finishing tool in every corner.
What corner R means for quoting
A 2D pocket corner radius sets the smallest cutter that can finish the wall-to-wall join without rest machining. If the drawing shows R1.0, a 2 mm finishing tool can theoretically reach it; if it shows R0.25, the shop must drop to a very small tool, add rest passes, or ask you to open the corner. Floor fillets are a different number: they follow the tool-nose radius of whatever end mill finishes the floor, and they can be larger than the corner R. Process pages for automation aluminum ([CNC 3-axis Al 7075 automation](https://3dwk.com/en/cnc-3axis/al-7075/automation.html), [CNC 5-axis Al 7075 automation](https://3dwk.com/en/cnc-5axis/al-7075/automation.html), [CNC 3-axis Al 7075](https://3dwk.com/en/cnc-3axis/al-7075.html)) assume those two notes when lots mix open pockets with tightly radiused interiors.
Do not leave “corners as CAD” in a notes cloud. Put **POCKET CORNER R3.0 MIN; FLOOR FILLET R1.0; NO SHARP INTERNAL CORNERS** on the PDF and mirror it in RFQ text. Background: [DFM checklist before an online CNC quote](https://3dwk.com/resources/dfm-checklist-before-online-cnc-quote), [deep pockets and tool reach on CNC quotes](https://3dwk.com/resources/deep-pockets-and-tool-reach-cnc-quotes), [what files to send for a CNC quote](https://3dwk.com/resources/what-files-to-send-for-cnc-quote).
Tool diameter, rest machining and depth
Corner R and pocket depth travel together. A generous R3.0 in a 12 mm-deep pocket is straightforward; the same depth with R0.5 asks for a long, thin tool or a rest-machine sequence after a larger roughing cutter. Five-axis tilting can sometimes reach a floor or undercut, but it does not erase a sharp 2D corner—see [five-axis aluminum housing design tips](https://3dwk.com/resources/five-axis-aluminum-housing-design-tips). If a mating insert truly needs a sharp corner, say so and expect EDM, a relieved dog-bone, or a rest-machine note rather than a silent solid.
Aluminum 7075 bar/plate sits in a higher planning band than 6061 under **rates.v1.1** material tables ([6061 vs 7075 aluminum for machined parts](https://3dwk.com/resources/6061-vs-7075-aluminum-for-machined-parts), [aluminum 7075-T6 vs T73 buyer notes](https://3dwk.com/resources/aluminum-7075-t6-vs-t73-buyer-notes)); material cost still is not the whole corner story—tiny-tool minutes and scrap risk in thin remaining walls are.
When a larger corner R is the right DFM move
Open the corner whenever the pocket is only clearing mass, hiding a cable, or locating a cover with clearance. Keep a smaller R only on functional nests that wrap a mating component, and name that exception on those corners alone instead of exporting one tiny radius everywhere. Dog-bone or T-bone reliefs at selected corners can preserve a sharp male insert while letting the cutter swing through; if you use them, show them in CAD rather than hoping the shop will invent the relief.
Tolerance and inspection traps
Calling “sharp corners” on a 15 mm-deep pocket, mixing an R0.2 CAD body with an ISO 2768-m title block, specifying a floor flatness that implies a large face mill while the corners still demand a 1 mm tool, or asking for 100% radius-gauge checks on every non-functional corner, all force **needs_manual**. Related: [ISO 2768 general tolerances on CNC RFQs](https://3dwk.com/resources/iso-2768-general-tolerances-cnc-rfq), [surface roughness Ra callouts that raise quotes](https://3dwk.com/resources/surface-roughness-ra-callouts-that-raise-quotes). If floor finish and wall finish differ, say so next to the fillet note—not in an unmarked cloud.
Illustration 1 shows an **Example part** pocket plate with labeled wall-to-wall corner R versus a separate floor fillet.
Example part walkthrough
**Example part:** Aluminum 7075-T6 plate ~80×60×15 mm, one 12 mm-deep rectangular pocket, ISO 2768-m general. With STEP + **POCKET CORNER R3.0 MIN; FLOOR FILLET R1.0; WALLS 2.0 THK MIN; NO REST-MACHINE SHARP CORNERS**, expect a usable automatic planning band on [quote-new.php](https://3dwk.com/quote-new.php). Same geometry with silent CAD showing R0.2 leftover from the solid model, and a note “corners as designed,” often lands DFM notes or **needs_manual**—without inventing any customer PO.
Illustration 2 contrasts a vague RFQ (“sharp corners as CAD”) versus a labeled corner-R pack and the clearer estimate path.
What widens bands fastest
Unlabeled sharp internal corners in deep pockets, corner R smaller than any practical finishing tool, floor fillet left implicit, and thin remaining walls beside a rest-machined corner. Quantity breaks help unit minutes but do not erase cutter-diameter ambiguity—see [how quantity breaks change CNC unit cost](https://3dwk.com/resources/how-quantity-breaks-change-cnc-unit-cost) and [what needs_manual means](https://3dwk.com/resources/what-needs-manual-means-preliminary-quote).
What to do next
Name a **minimum pocket corner R** and a **floor fillet**, open non-functional corners, then upload on [quote-new.php](https://3dwk.com/quote-new.php). Service pages: [CNC machining](https://3dwk.com/cnc-machining-service.php), [materials](https://3dwk.com/materials.php). Treat **rates.v1.1** min/mid/max as estimates, not invoices. If the UI shows **needs_manual**, answer the corner-R questions rather than forcing a fake firm price.
Common questions
Is a larger corner radius always cheaper?
Usually yes under **rates.v1.1** estimates, because a larger finishing tool is stiffer and needs fewer rest passes. The exception is a functional nest that must wrap a mating part—name that exception rather than sharpening every corner.
Can I leave floor fillets “as the tool decides”?
You can if you say “floor fillet R1.0 REF / TOOL NOSE” (or similar). Silence lets one estimator assume a sharp floor and another assume a large nose radius.
Do I need five-axis to solve sharp corners?
Not by itself. Tilting helps some floors and undercuts; a sharp 2D corner still needs a small tool, a relief, or EDM. See [CNC pockets, thin walls and undercuts](https://3dwk.com/resources/cnc-pockets-thin-walls-undercuts).
How should I inspect corner R?
Call a radius gauge or optical check only on functional corners. Inspecting every leftover CAD radius as if it were a sealing feature usually over-controls the lot.