From 5700b41aaa79da5cafa3de519c2d1a4fb969e04a Mon Sep 17 00:00:00 2001 From: Sam Calisch <sam.calisch@cba.mit.edu> Date: Thu, 20 Dec 2018 16:22:58 -0500 Subject: [PATCH] Update README.md --- README.md | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/README.md b/README.md index 006d3dc..418c569 100644 --- a/README.md +++ b/README.md @@ -28,11 +28,13 @@ We toolpathed the microspline part at the full ~2" long scale. This would be cut Given the long machining time, we ultimately decided to do a 1/3-scale test cut from a stack of 0.01" brass sandwiched between 0.25" aluminum. The perimeter of this toolpath measures 17.5 inches. With an expected cut speed of 0.18 inches/minute, the expected cut time is just about 100 minutes or 1 hr 40 mins. -## Micromachining +## Micromachining using Zund G-3 L-2500 -Using a .030" diameter end mill with amorphous diamond coating (<a href='http://www.harveytool.com/ToolTechInfo.aspx?ToolNumber=72030-C4'>Harvey Tool 72030-C4</a>), we machined the flexure from .020" Aluminum 2024 sheet in 2.5 minutes (comparable to the waterjet). +Despite being a very large-scale tool, the Zund was surprisingly effective at micromachining with its 50kRPM router spindle. To fixture the stock, we first faced a sheet of aluminum to provide a rigid surface. Then we applied PSA tape to both this surface and the underside of the stock. We burnished the tape using a small stainless rod. Then we applied CA glue to the tape and bonded the stock to the substrate. -Here is a 50% scale flexure (.010" beams, .015" gaps) machined from .020" thick Aluminum 2024 sheet using a .015" diameter end mill with amorphous diamond coating (<a href='http://www.harveytool.com/ToolTechInfo.aspx?ToolNumber=72015-C4'>Harvey Tool 72015-C4</a>). It was fixtured using burnished PSA tape to both the substrate and the stock, with CA superglue applied between the tape layers. +Using a .030" diameter end mill with amorphous diamond coating (<a href='http://www.harveytool.com/ToolTechInfo.aspx?ToolNumber=72030-C4'>Harvey Tool 72030-C4</a>), we machined the flexure from .020" Aluminum 2024 sheet in 2.5 minutes (comparable to the waterjet). 300um step down, 20 mm/s, 50kRPM. + +Here is a 50% scale flexure (.010" beams, .015" gaps) machined from .020" thick Aluminum 2024 sheet using a .015" diameter end mill with amorphous diamond coating (<a href='http://www.harveytool.com/ToolTechInfo.aspx?ToolNumber=72015-C4'>Harvey Tool 72015-C4</a>). This took about 8 minutes, but I think could be run faster. <img src='images/flexure-0.5-penny.jpg' width=300px> -- GitLab