Scraper, also known as marking board, is made of bamboo or laminate. It is a tool for small motors to insert wires. When inserting the wire, use the insulating paper of scraper to separate the slot, straighten the wire that has been laid into the slot, and push it to both sides of the slot, so that the wire embedded behind can easily enter the slot. When making scraper, the scraping part (front end and both sides of front end) shall be rounded with a file and polished with sandpaper to avoid scraping the insulation layer of conductor and the insulation paper at the bottom of groove, with a width of 2cm ~ 3cm.

For some castings with specific shape, if the production quantity is small, the scraper can be made of a piece of wood plate suitable for the section shape of the casting without pattern. During the molding, the scraper moves back and forth along a certain track or rotates around a fixed central axis to scrape out the required cavity. This method of molding and core making without pattern is called scraper molding. Scraper is a common modeling method with simple production and few materials. The common ones are rotary scraper modeling and guide scraper modeling.

In the actual production, it is decided by the shape and size of the casting whether to use the rotary scraper or the guide scraper. The short and thick cylinder is modeled by rotating scraper, while the longer cylinder or other special-shaped main body with guiding surface is modeled by guiding scraper. As for whether to use the scraper or the real sample mold, it should be decided after comprehensive consideration of the production quantity, economy, quality and technical requirements of the castings.