Melt electrowriting, a high‐resolution additive manufacturing technology, has so far been developed with vertical stacking of fiber layers, with a printing trajectory that is constant for each layer. In this work, microscale layer shifting is introduced through deliberately offsetting the printing trajectory for each printed layer. Inaccuracies during the printing of sinusoidal walls are corrected via layer shifting, resulting in accurate control of their geometry and mechanical properties. Furthermore, more substantial layer shifting allows stacking of fiber layers in a horizontal manner, overcoming the electrostatic autofocusing effect that favors vertical layer stacking. Novel nonlinear geometries, such as overhangs, wall texturing and branching, and smooth and abrupt changes in printing trajectory are presented, demonstrating the flexibility of the layer shifting approach beyond the state‐of‐the‐art. The practice of microscale layer shifting for melt electrowriting enables more complex geometries that promise to have a profound impact on the development of products in a broad range of applications.

Additive manufacturing technologies based on layer-by-layer deposition of material ejected from a nozzle provide unmatched versatility but are limited in terms of printing speed and resolution. Electrohydrodynamic jetting uniquely allows generating submicrometer jets that can reach speeds above 1 m s −1 , but such jets cannot be precisely collected by too slow mechanical stages. Here, we demonstrate that controlling the voltage applied to electrodes located around the jet, its trajectory can be continuously adjusted with lateral accelerations up to 10 6 m s −2. Through electrostatically deflecting the jet, 3D objects with submicrometer features can be printed by stacking nanofibers on top of each other at layer-by-layer frequencies as high as 2000 Hz. The fast jet speed and large layer-by-layer frequencies achieved translate into printing speeds up to 0.5 m s −1 in-plane and 0.4 mm s −1 in the vertical direction, three to four orders of magnitude faster than techniques providing equivalent feature sizes.

typing boundaries of complexity, resolution, and production speed. [1] Nevertheless, every AM technology has its limits in terms of realizable feature sizes and shapes, restricting its application for various products. A difference between the design and the actual produced part varies from method to method but can be quite noticeable. [2,3] One such AM technology susceptible to this effect is melt electrowriting (MEW), where an electrohydrodynamically stabilized molten polymer jet is direct-written at low flow rates onto a collector. [4] Using repeated layer deposition, these small-diameter fibers can be assembled using AM principles for the fabrication of microscale structures. [5] While the fiber diameter for optimized MEW can be accurately set and stay constant throughout a print (coefficient of variation <5%), [6] there remains a challenge in precisely predicting the fiber placement that necessitates manual parameter or printing path adjustment to obtain the desired structure. [7] This lack of predictability is, in turn, limiting the research and potential industrial utilization of the technology. The predictive ability is especially compromised when printing curved elements, that are increasingly important for mimicking the morphology and mechanical properties of the living tissues. [8] In this context, most MEW research currently uses linear laydown patterns, as this morphology is least affected by changes in the direct-writing direction. There is a clear discrepancy between the programmed stage movement and the deposited fiber shape (i.e., laydown pattern) most noticeable with curved MEW structures, as well as at edges where the linear portion of the direct-written fiber ends. The main reason behind this discrepancy is the gap between the nozzle and collector, which is bridged by the viscoelastic jet. Figure 1A schematically shows how the relative movement of the nozzle to the collector results in a jet lag, a line segment between the nozzle position (NP) and the jet contact point (JCP) on the collector (Figure 1A,B). Whereas the NP velocity (V NP) corresponds to the actual collector velocity, the JCP velocity (V JCP), that represents the actual fiber deposition velocity, will often be different from it. [7,8] Due to the MEW jet lag, the changes in direction and speed of the collector movement are not followed by the same changes in the printed fiber pattern (Figure 1C). [9,10] Compounding this issue is that the lag is variable and sensitive to changes in both instrument (i.e., applied pressure/ voltage) [11] and environmental (i.e., temperature/humidity) parameters. This is the reason why the elimination of fiber pulsing during MEW is so important for the reproduction of samples. [6] One approach to this fiber-placement problem is by minimizing the MEW jet lag. [12] Decreasing the collector speed to

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