Apr 5th 2021
In our last installment of our three-part series on keeping safe while working with carbon fiber & composites. In our second installment we focus on Trim, Drill & Sanding Safety.
Trim, drill, and sanding safety is straightforward, with a few additions from the above sections. Clean working environments, cut-resistant gloves, and safety glasses help provide personal protection when working with any composite. A clean working environment for machining composites generally includes an area dedicated to these processes. This area could be inside or outside but should keep electrical components that are not needed and other media to a minimum.
Electrical vs. Pneumatic tools is different from a safety perspective and must be protected as such. The use of pneumatic tools reduces the chance of electrical shock or fire hazards. Electric-powered tools will tend to run hot, whereas pneumatic tools will stay cooler. If using electrical tools, keep other connections away and isolated from cutting and sanding operations if possible. Using a single plug or use of an extension cord for an electrical tool is good practice. Keep dust away from electrical components as much as possible, mitigating possible hazards. When cutting thicker laminates, keep a watchful eye on the tools' temperatures to make sure they do not overheat.
When doing any cutting, drilling, or sanding, dust becomes a hazard. It is best practice to eliminate possible sources of dust and fine particle exposure to the lungs. These processes cause possible irritation from dust particles. The use of a downdraft booth is commonly used in many industrial applications to mitigate dust accumulation. Also, it is of utmost importance to keep accumulating dust particles from landing on any computer equipment or other possible electrical hazards. However, downdraft booths are relatively expensive. A cheaper alternative is using a shop vac or vacuum cleaner with a hose attached near the sanding or cutting area; this will draw the dust away from the area being sanded, keeping the area clean and keeping dust from irritating skin or lungs. Filters used in a shop vac should be capable of entrapping particle sizes of 0.2 microns or less as dust particles from carbon fiber, and other materials can reach ~0.2 microns. Most filters listed under "fine-dust" will usually suffice for efficient particle collection.
As another added layer of safety, a box fan or equivalent may be used across the part to propagate accumulating dust out and away from the immediate area of work being performed. This option is best utilized in an outdoor environment as dust particles would not be blown onto or into other pertinent surfaces.
Cleanliness in composites is a must, and even with a shop vac handy while working in a downdraft booth and/or using a fan outdoors, a respirator should always be worn while any cutting, grinding, drilling, or sanding processes are being performed. There are a wide variety of respirator options available. Reusable options in a half-face cover offer optimal protection against dust and other hazards, while a simpler N-95 mask may suffice for smaller areas or while only drilling holes. The mask must make contact with the skin as much as possible. Some cheaper masks or differing types do not make enough contact with the face, allowing dust to irritate lungs or skin possibly.
Part Safety: When drilling or cutting thicker laminates, pay caution as heat will accumulate quickly on cutting blades or drill bits. Wet sanding/cutting options will keep the composite cool while performing these tasks, though not always needed. After cutting or drilling, do not immediately take the bit or saw blade off as it will be hot. Wearing cut-resistant gloves will also mitigate the chance of coming in direct contact with the potentially hot surface.
Tip: While sanding laminates, dust accumulation incoming to the face or skin may be mitigated by merely swapping the direction of circular bits. If possible, have the diamond wheel or sanding block going into the laminate, away from whom is performing the cut. Doing it this way will have particles going toward the floor instead of pieces and particles coming off the part and being blow into facial other bodily areas. Clear face shields may also be utilized to eliminate issues when chips or pieces of laminates come back toward facial areas.
Additional hazards as part of the process are possible exposure to unsafe noise levels as part of trimming laminates. It is advised to wear earplugs when trimming or sanding laminates to reduce any effect on hearing.