4556
Similarly , lack of fusion pores are shown to occur following scan tracks in situations of poor hatch overlap , or a similar but different distribution of lack of fusion porosity due to large layer height spacing , showing respectively vertical and horizontal lack of fusion pore morphologies .
 fusion, overlap, distribution, fusion, layer height, vertical, fusion, morphologies
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: manufacturing standard, machanical property, manufacturing process, material, engineering feature, process parameter, machine or equipment, application, process characterization, enabling technology, biomedical, concept or principle 
Text: {0} 
Answer:
 fusion, overlap, distribution, fusion, layer height, vertical, fusion, morphologies