Per the Form D the "Date of First Sale" was 2013-07-18 and all 21 of the sales were completed when the Form D was issued on 8/1/13. Therefore six months would be 1-18-14.
Can't tell if all of the investors paid their money on 7/18/13, so all of the shares may become un-restricted on 1/18/14 or some may be un-restricted in the week or two after 1/18. The clock starts when each investor actually pays for their shares per the regulations.
From post 9050:
Rich, the holding period for PP can be found on the SEC website. There is a "readers digest" version in their Answers section.
However this version does not give you all the answers and is frequently misquoted. If you want the complete facts, you need to dive into the actual Code of Federal Regulations Part 230.
Start with 230.506 (Exemption for limited offers and sales without regard to dollar amount of offering) which includes the exemption from registering the shares included in the Form D. 506 requires the limitations in 501 and 502 be met and 502 requires the securities to be restricted from resale.
To determine how long the restriction is required to be, you go back up to section 230.144. 144 breaks it down into reporting and non-reporting companies. Shares from reporting companies have a six month minimum before resale and non-reporting companies have a one year minimum.
SGLB is current in its financial reporting (10-Ks, 10-Qs, etc) so I would expect the PP shares would be restricted for six months. After the six months, the share certificates would have to be processed to remove the restriction legend before they could be sold. This process can take some time since it can involve a company lawyer, the transfer agent and your brokerage.