First deposited layer
with Pam 3D printers
The last step is the interpretation of the Gcode into a system command to perform the printing.
Pam systems operate by successive deposition of melt obtained by direct extrusion of pellets. The first stage of the printing process is the realization of the first layer in immediate contact with the printing plate.
The challenge of this first layer is to ensure an optimal cohesion with the printing plate in order to offer a robust base for the continuation of the printing process.
This parameter strongly influences the printing strategy and the orientation of the part to be 3D printed. Indeed, to offer the best possible base, the largest possible flat surface of the part is to be preferred.
The first layer is applied to the platen with a low layer height in order to sufficiently crush the material and thus optimize the adhesion to the printing platen. Since the first layer deposited is more crushed than the following layers, the printed part may have a slightly flared appearance at its base called "elephant foot".
To compensate for this undesirable dimensional effect, it is advisable to provide a slight chamfer at the base of the part.
Another undesirable effect to be taken into account in the print platen/part interface is warping of the part due to material shrinkage during cooling. There are several possible solutions to overcome this problem.
When modeling, it is recommended to avoid sharp angles and to use rounded corners (if possible in accordance with the diameter of the nozzle used) which present less risk. It is also conceivable to foresee elements to be printed at the corners which reinforce the adhesion to the plate and will be removed at the end of printing.
In the preparation of the printout with the part cutting software, it is also possible to automatically generate structures around the part. For this purpose, brime, skirt and raft structures are available in the software.
The heating plate and the radiant plate can be adjusted to mitigate these effects by better control of the cooling of the part.
Finally, specific equipment can be used during printing. The application of an adhesive, glue or lacquer on the platen ensures better adhesion depending on the material used. It is also possible to choose to print on a micro-perforated tray in order to combine mechanical and chemical adhesion.
Synthesis of the rules for the first deposited layer
|Constraint and element||Proposed
|Stage of the 3D printing chain||Good
|Provide a robust print base that maximizes adhesion to the printing plate.||Choose a print orientation that takes the largest flat surface of the part as the basis for printing.||Slicing||Position the largest flat surface in contact with the platen as the printing base.|
|Propose a geometry offering a large flat surface||Modeling||Integrate a sufficient flat surface when designing|
|Elephant foot effect||Integrate a chamfer at the base of the part||Modeling|
|Warping / plate detachment||Rounding sharp corners||Modeling||Avoid sharp corners and draw a fillet corresponding to the diameter of the nozzle to be printed|
|Add reinforcement elements at the corner||Modeling||Plan geometries adapted to the corners of the surface in contact with the table top|
|Add an brim, skirt or raft type structure||Slicing|
|Use and adjust the temperatures of the heating plate and the temperature radiator||Slicing & 3D printing process||When these effects appear, increase the temperature of the tray and use the temperature radiant|
|Prepare the printing plate to optimize the chemical adhesion with the material.||3D printing process||Depending on the printed material, identify the appropriate substrate to prepare the tray for printing|
|Use a microperforated buildplate||3D printing process||In cases where chemical adhesion is insufficient, choose mechanical adhesion|
Let’s dive into the possibilities offered by PAM
From pellets to object, PAM technology offers the most direct process to high performances end-parts.
Metals Ceramics Commodity Elastomers Performance High Performance.