New Delhi, March 31 Zetwerk Manufacturing has filed preliminary documents with the market regulator, Sebi, through a confidential channel for an initial public offering (IPO) to raise between ₹4,000 crore and ₹5,000 crore.The proposed offering is expected to include a fresh issuance of equity shares and an offer for sale (OFS) by existing shareholders, with details on the size and valuation to be finalized through the book-building process, according to people familiar with the development.The manufacturing marketplace counts investors such as Khosla Ventures, Baillie Gifford, Rakesh Gangwal, Accel, Peak XV, and Lightspeed among its backers.In a public notice on Tuesday, Zetwerk said it has filed "the pre-filed draft red herring...