20S highlights the Additive Manufacturing Specification Level ( AMSL ) which dictates the degree of testing needed to proof the process and provide confidence to the stakeholders . The AMSL testing ( comprising both Destructive and Non-Destructive Tests ) differs in accordance with 3D printing manufacturing processes such as “ Powder Bed Fusion ( Laser Beam , LB or Electron Beam , EB )”, “ Directed Energy Deposition ( Wire and Blown Metal Powder )”, and “ Binder Jetting ”. Currently , metal 3D printing produced from “ Powder Bed Fusion ” is more common than other processes in the local market ; thus it will be discussed further in this article . The goal for metal 3D printing testing is to prove that the product material characteristic is equivalent to that from conventional manufacturing processes ( for safety and quality purposes ).
Key Notes :
● Both standards API 20S and DNV- ST-B203 differ to a certain extent , but nonetheless the basic principles are almost the same .
● Additive Manufacturer Quality Management System ( QMS ) together with associated processes can be established in parallel with ISO 9001 for company implementation .
In order to produce a successful product , there are three vital elements that needs to be carefully considered : “ Equipment ”, “ Process ”, and “ People ” whereby the first two elements fall under the Printing Equipment Qualification in API 20S . All advanced machines require both hardware and software to co-function to be effective , including Additive Manufacturing ( 3D Printing ). Hence , the manufacturer needs to possess a proper “ Preventative Maintenance Plan ” and “ Digital Product Definition ”. The maintenance plan shall cover the requirements on equipment calibration , inspection , servicing , and cleaning frequency , including the supply system for power and gas . Proper recording needs to be preserved for audit purposes .
The “ Process ” itself in Additive Manufacturing ( AM ) is another critical aspect for metal 3D printing . There should be a QA strategy approach in terms of the manufacturing flow process and consumable handling , including the consumable criteria . The “ First Article ” which can be considered as a pilot / test run meant for verification is to proof the process prior to the subsequent production phase . Howbeit , any failure in the required first article testing and any changes to the “ Essential AM Variable ” will require another first article sample run . As mentioned , the degree of first article testing is per AMSL . Also , engineers can include additional tests according to ASTM material properties and customer requirement .
Human intervention is generally the last line of defense to prevent any bad products and should not be underestimated by any parties . Competency of personnel ( in terms of Education , Training , Skills , and Experience ) is highlighted in API 20S on the AM Operator , NDE technician and QC Inspector . On top of that , the employer needs to put proper company procedures , work instructions and necessary recording in place . For example , manpower : product involvement starts from the initial design stage , metal printing phase , and final product quality inspection before release to end user . Thus , there are many opportunities to improve and control the AM process . Clearly , the human factor is vital to the success on the overall product .
In API 20S , Section 7 mentioned the “ Production Component Quality Control Requirements ”, which means batch testing in layman language . Basically , a few samples will be randomly chosen from the whole production lot for testing and evaluation purposes . Similar to the first article sample run , both Destructive and Non-Destructive Tests exist , but generally in lesser quantities . Normally , all quality control activities shall be governed by the additive manufacturer ’ s documented procedures ( QC Procedure ), which would include appropriate methodology and acceptance criteria . The objective of these controls is to thoroughly scrutinise the product from the aspect of Quality and Safety prior to moving to the next stage .
In conclusion , there are advantages in 3D printing for metal products compared to the conventional subtractive manufacturing , such as the relative speed in the production of complex shaped parts , customised products and low material waste , just to mentioned a few . Nonetheless , some of the downsides are the higher production costs due to the equipment and raw material ( metal powder ), and the limitation
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