Flat Pattern

48"×80.5" blank · X = 4' side (left/right) · Y = 8' side (front/back) · Two CNC setups, grooves on both sides.

Blank

X (left/right)48.0"

Y (front/back)80.5"

MaterialHDPE 3/8"

Stock4'×8'

Setup 1 — Inside Face Up

8 INSIDE grooves (solid green)

4 outside grooves on back (ref)

Bit45° V-groove

Depth0.281"

Cut the 8 green lines before flipping.

Setup 2 — Outside Face Up

4 OUTSIDE grooves (solid red)

8 inside grooves on back (ref)

Perimeter cut-through

Bit45° V-groove + end-mill

Depth0.281" grooves / full perimeter

Flip sheet end-for-end (rotate 180° along Y). Re-zero X0,Y0 at new bottom-left corner.

Outside grooves — why?

The lip (top edge) and shelf bends are convex from the outside — material compresses on the exterior face. All other bends are concave from outside, compressing on the interior face.

Groove positions (Y axis)

INSIDE @ Y=6.5"upper trans / main

INSIDE @ Y=24.5"main / lower-A

INSIDE @ Y=26.5"lower-A / shelf

INSIDE @ Y=34.5"lower-B / bottom

INSIDE @ Y=46.0"bottom / lower-B

INSIDE @ Y=54.0"shelf / lower-A

INSIDE @ Y=56.0"lower-A / main

INSIDE @ Y=74.0"main / upper trans

OUTSIDE @ Y=2.5"lip / upper trans

OUTSIDE @ Y=30.5"shelf / lower-B

OUTSIDE @ Y=50.0"lower-B / shelf

OUTSIDE @ Y=78.0"upper trans / lip

Setup 2 Y values are post-flip G-code coordinates (new Y0 at bottom-left after flip).

Setup 1 — Inside Face Up Cut 8 green V-grooves · 0.281" deep · 45° bit · grooves run full X (0→48")

↕ FLIP END-FOR-END · re-zero X0,Y0 ↕

Setup 2 — Outside Face Up Cut 4 red V-grooves · then perimeter cut-through · Y coords are post-flip