AMERICAN NATIONAL STANDARDS INSTITUTE, or ANSI, is a good resource for the below documents and can be (or will soon be) obtainable from the online standards store – A licensee of both SPI and B11 Standards.
ANSI/SPI B151.1-2007 (R2012) Horizontal Injection Molding Machines ‑ Safety Requirements for Manufacture, Care, and Use (under revision; expected Q1 or Q2, 2014)
ANSI/SPI B151.29-2002 (R2012) Safety Requirements for the Manufacture, Care and Use of Vertical Clamp Injection Molding Machines (VCIMM) (under revision; expected Q4 2013)
SPI Publication No. AN116 (Aug.2001) Recommended Guideline for Robot Injection Molding Machine Electrical Interface
ANSI/SPI B151.27-2013 Safety Requirements for the Integration of Robots with Injection Molding Machines (currently in final stages of revision – anticipate ANSI approval in September 2013)
ANSI B11.19-2010 Performance Criteria for Safeguarding (this is a general safeguarding standard that applies across the broad range of machinery, not just plastics machines)
ANSI B11.0-2012 Safety of Machinery – General Requirements and Risk Assessment (this is also a general safety standard that applies across the broad range of machinery, not just plastics machines)
The first (4) documents may also be obtained through the plasticsindustry.org website.