Objective The batik painting process in traditional batik dyeing is highly dependent on the personal experience of craftsmen, and there are some problems such as high technical threshold, long painting time, difficulty in maintaining consistency of painted patterns and high labor intensity, which seriously restrict the industrialization promotion and cultural inheritance of batik dyeing process. By integrating human factors engineering and fused deposition modeling (FDM) 3D printing technology, and innovatively applying human factors engineering principles to the design of mechanical systems, the modified design of a 3D printing wax-painting machine is completed. The feasibility of this design is verified through batik painting experiments, promoting the innovative application and standardized production of batik leather products.

Methods The action execution logic of batik painting in the traditional batik process is deeply analyzed, which is decomposed into four kinds of bio-mechanical systems: path planning system, motion control system, wax liquid extrusion system and temperature control system. The mapping model between batik painting action and FDM in the traditional batik dyeing process is established. The process of traditional batik artisans drawing rough drafts by hand is transformed into digital code programming. The motion control is replaced by a three-axis mechanical system, the batik painting action is reconstructed as a melting extrusion device, and the manual judgment of batik temperature is upgraded to a closed-loop temperature control device. The spiral feeding and non-contact batik application mechanism using FDM technology is implemented to replace the traditional batik dipping action, thereby adapting to the characteristics of vegetable-tanned cowhide. The experiment focuses on the core variables of wax particle mixing ratio (bee wax: paraffin wax ratios are 2∶8, 3∶7, 4∶6) and printing temperature (70 ℃, 75 ℃, 80 ℃), aiming to systematically test the stability and process compatibility of the device.

Results Under the condition of good device testing, indigo dyeing solution is used to conduct immersion dyeing experiments on the vegetable-tanned cowhide leather after batik painting, verifying the feasibility of automatic batik painting by the 3D printing batik painting machine. Experimental data show that under the conditions of a mixture ratio of beeswax to paraffin of 2∶8 and a printing temperature of 80 ℃, the pattern boundaries are clear, the lines are continuous, the anti-dyeing effect is the best, and there are no obvious blurring or uneven penetration problems. This significantly improves the efficiency of the batik painting process and the accuracy of the batik pattern in the batik dyeing process, and solves the randomness drawback of manual batik painting.

Conclusion The 3D printing batik painting machine can stably and continuously apply batik on the surface of vegetable-tanned cowhide leather. It innovatively addresses the core issues of low efficiency, insufficient precision, and difficulty in standardization of traditional batik painting techniques when applied to vegetable-tanned cowhide leather, and effectively enhances the artistic expression of batik dyeing leather products. It not only provides a foundation for the modernization inheritance of the batik painting intangible cultural heritage, but also promotes the standardized application of batik painting in leather dyeing. Future research can be expanded to include dyeing tests on different leather materials, and can further enrich the pattern expression through layer-by-layer wax application or parametric modeling, promoting the customized production of batik dyeing leather in fields such as clothing and home furnishings.