num="0038">Compared with other designs, injecting material 126 into a cavity 124 according to aspects of the current disclosure (block 308) can utilize reduced injection pressures can result from injected material 126 flowing into the cavity 124 through the gate 164 and toward both ends 174, 176 of the cavity 124, such as generally illustrated in FIGS. 4-6. FIG. 4 shows a cavity 124 prior to injection. FIG. 5 shows the cavity 124 during injection, with injected material 126 flowing from the gate 164 in the center section 170 toward the first end 174 and toward the second end 176 (e.g., simultaneously in opposite directions). FIG. 6 shows the cavity 124 after injection is complete or substantially complete, with injected material 126 having flowed from the center section 170 to both ends 174, 176.

Aspects of the present disclosure can involve injecting material 126 in a center section 170 instead of injecting at one end and requiring the injected material 126 to flow substantially the entire length 124L of the cavity 124, as is done with some other designs. For example, the length of a flow path 166 of some or all injected material 126 can be 60% or less of the length 124L of the cavity 124, and can be 55% or less, and/or about 50% of the length 124L. In some configurations the length 124L can be at least 6 inches, at least 7 inches, and/or in a range of about 6 inches to about 7.75 inches. For example, a range of 5.5 inches to 8.0 is contemplated. Reduced flow path lengths can reduce cooling of the material 126 during injection, which can reduce injection pressure. For example, with longer flow paths, the material 126 reaches lower temperatures, which increases viscosity and can require increased fill times or increased injection pressures to maintain fill times.

Some other designs, with injection at an end of a cavity, were developed from cold runner applications and applied to thermal gate and valve gate technology. Since those designs have been used with non-biodegradable materials having lower viscosities (e.g., polyethylene, polystyrene), high injection pressures have not been needed, so high clamping pressures associated with high injection pressures have also not been an issue.

According to an aspect of the present disclosure, and as generally illustrated in FIGS. 7-9, injection molded cutlery 200, such as formed via one or more aspects of the system 100 and/or the method 300, can include a body 202 defining a handle portion 204 and a utensil portion 206, and having an injection gate mark 208 located at a center section 210 of the body 202. The center section 210 of the cutlery 200 can correspond to the center section 170 of the cavity 124. For example, the center section 210 can include 20% of the total volume of the cutlery 200 and can include and/or be centered at the volumetric center 212 of the cutlery 200. The center section 210 may include parts of either or both of the handle portion 204 and the utensil portion 206. According to an aspect of the present disclosure, the body 202 can be made from a bio-material 126 injected at a pressure that is less than 60% of an injection pressure required for injection at an end of the body 202. For example, to fill a particular cavity 124 in a specific time frame, such as in 2 seconds or less, injection according to aspects of the present disclosure that inject at a center section 170 can utilize injection pressures that are less than 60% of injection pressures that would be required to fill the same cavity 124 in the same time frame by injecting at the end of the cavity 124.

In one aspect of the present disclosure, such as generally illustrated in FIGS. 7-9, the cutlery 200 includes an injection gate mark 208 that is located in the center section 210. The injection gate mark 208 can be formed via the gate 164 during injection molding of the cutlery 200 (block 308). The injection gate mark 208 can include a protrusion that extends, at least to some degree, from the body 202, some form of deformation/indentation, and/or other visible indication on the body 202 of the position of the gate 164 during injecting. The injection gate mark 208 can be located at a first side (e.g., a top side) or a second side (e.g., a bottom side) of the cutlery 200, but can be located in other locations depending on the position of the gate 164 relative to the cavity 124. With some configurations, the center section 210 includes a section of the handle portion 204 and the injection gate mark 208 can be disposed in that section of the handle portion 204.

According to an aspect of the present disclosure, a body 202 of cutlery 200 can be made via injection molding with a bio-material or biodegradable plastic, such as Polyhydroxyalkanoate (PHA). Additionally or alternatively, the bio-material or biodegradable material comprises cellulose acetate and/or a bio-resin based material. The viscosity of the bio-material or biodegradable plastic can, for example and without limitation, be at least 100 Pa·s at a shear rate of 1000 1/s and a temperature of 180 degrees Celsius. Non-biodegradable materials (e.g., polypropylene), may include significantly lower viscosities, such as 60 Pa·s at a shear rate of 1000 1/s and a temperature of 240 degrees. This higher viscosity of bio-materials can result in using injection pressures that are nearly double when injecting at the end of a cavity. The increased injection pressures also increase clamping force and/or reduce the number of cavities per mold. Embodiments of the present disclosure can reduce or eliminate the effects of these increased injection pressures, increased fill times, increased clamping forces, and/or cavity reduction. For example, embodiments of the present disclosure may be 50-100% more efficient than if bio-material is injected at the end of a cavity.

According to an aspect of the present disclosure, injection molded cutlery 200 is biodegradable and/or compostable, such as in a composting facility and/or for home/backyard composting. In some instances, the cutlery 200 can be sufficiently biodegradable and/or compostable to comply with one or more standards or certification requirements, such as ASTM D6400 (e.g., ASTM D6400-22), ASTM D6868, European Standard EN 13432 (e.g., BS EN 13432:2000), European Standard 14995, International Biodegradable Products Institute (BPI) BPI Commercial Compostability Certification Scheme (e.g., version 2.4), and/or TÜV AUSTRIA “OK compost HOME”. For example, cutlery 200 may be formed to reach or exceed 90% disintegration in a particular timeframe and/or environment, such as in a municipal, commercial, and/or industrial composting facility (e.g., 55-60 degrees Celsius) within 12 weeks, or in a home/backyard composting environment (e.g., 20-30 degrees Celsius) within 6 months or 180 days. Additionally or alternatively, cutlery 200 may be formed to reach 90% biodegradation (e.g., conversion of the carbon in the cutlery 200 to carbon dioxide) in a particular timeframe and/or environment, such as in a municipal, commercial, and/or industrial composting facility (e.g., 55-60 degrees Celsius) within 6 months or 180 days, or in a home/backyard composting environment (e.g., 20-30 degrees Celsius) within 12 months or 365 days. Municipal, commercial, and/or industrial composting facilities may provide environments with higher temperatures than home/backyard environments, so testing for standards/requirements for municipal, commercial, and/or industrial compostability may be conducted at higher temperatures (e.g., 55-60 degrees Celsius) than for home compostability (e.g., 20-30 degrees Celsius).