## 4 Conclusions  
As a result of research on newly developed CLWD technology for advanced use in the additive remanufacturing of cutting tools made of hard-weldable high-speed steels, two sets of process parameters were developed, i.e., low and high heat input sets. Deposited structures that met the qualitative (no cracks) and geometrical requirements based on the dimensions of the row of teeth of the tool under consideration (the broach) were obtained.  
1. Single clads deposited without preheating are susceptible to cracking because of two negative factors, i.e., softening of the material at the HAZ boundaries and high shrinkage stresses induced by the relatively large size of the solidifying material. Furthermore, the accumulation of stresses in the multilayer process results in cracking for all tested sets of process parameters.
2. The average hardness of the deposited single clad at the high heat input is 6 to 7% lower than the one obtained for low heat input. Both results are comparable to the hardness of the substrate material.
3. Applying preheating to the temperature above Ms (320 \({}^{\circ}\)C), it is possible to obtain multilayer deposited structures over 2.5 mm in height that are crack-free.
4. Processing with a higher travel speed allows for achieving a finer continuous grid of carbides without clusters as well as a fine dendrite microstructure of the matrix. This microstructure is more beneficial in terms of the considered application.
5. Preheating of the substrate material leads to thickening of the carbide grid and the growth of matrix grains. This also affects the widening of the softening zone in the substrate material.
6. The multilayer CLWD process with lower heat input has a positive effect on the HAZ by reducing its maximum hardness value. Additionally, the tempered zone in the substrate material is narrower than in the case of a higher heat input multilayer process.  
Figure 15: Results of hardness measurement for multilayer structures deposited with preheating (T\({}_{0}\): 320 \({}^{\circ}\)C): (**a**) parameter set No. 1—high heat input (3 layers), (**b**) parameter set No 7—low heat input (8 layers).  
However, the technology presented in this article concerns the first stage of remanufacturing, i.e., the additive deposition of an appropriate volume of material in order to reproduce the geometry of cutting tools. The newly developed CLWD technology allows the approximate shape of the flat broach teeth to be regenerated, accepting a grinding allowance. In order to fully qualify the innovative tool reconditioning method, it is necessary to carry out grindability tests and functional tests of remanufactured tools.  
Conceptualization, J.R. and J.K.; methodology, P.K. and J.K.; software, P.K.; validation, P.K., J.K. and R.D.; formal analysis, J.K and R.D.; investigation, P.K. and R.D.; resources, P.K. and J.R.; data curation, J.K.; writing--original draft preparation, P.K.; writing--review and editing, J.K. and J.R.; visualization, P.K. and J.K.; supervision, J.R.; project administration, P.K and J.R.; funding acquisition, P.K and J.R. All authors have read and agreed to the published version of the manuscript.  
The work presented in this publication was carried out within the project \"Excellence Initiative--Research University\" (Polish acronym IDUB), budget number 8211204601, task \"Development of a system for coaxial hot filament laser deposition with the use of additional heat sources\".  
Not applicable.  
The data during the research are available from the corresponding author on reasonable request.  
The technological partner of the research was TCM Poland Tool Consulting & Management LLC, Polkowice, Poland.  
The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.