Under-Adhesion
Under-Adhesion
A part is partially or completely detached from the platform during printing.
How to Identify
Under-adhesion can be diagnosed as follows:
- Part partially detaches from the platform
- Look for areas not connected to the platform
- Look for features not fully resolved at platform-adhered surfaces
- Part falls off the platform during printing
- Look for the part in the cassette
- Slices cured after the part fell off the platform will be on the window
- Part outline on the platform is incorrect after part removed
Cause - Undercut
Solution - Print Preparation or Part Design
Cause - Unvented volume
Solution - Print Preparation or Part Design
Cause - Inconclusive
Cause - Inconclusive
Cause - Asymmetrically oriented part
Solution - Print Preparation or Part Design
Cause - Small to large cross section later in the print
Solution - Print Preparation or Part Design
Cause - Unvented volume
Solution - Print Preparation or Part Design
Troubleshooting
It is recommended that you review all the possible solutions before taking action to ensure you are pursuing the best course of action.
If the best course of action is not apparent, try the troubleshooting options in the order listed. Refer here for more tips.
Process, Material, and Hardware Checks
If any of these conditions apply to your print, take the corrective action and reprint to see if the problem is resolved.
Diagnostics
If the above checks & actions did not resolve the issue or do not apply to your print, the following diagnostics may further inform what is causing the issue.
Print Preparation or Part Design Adjustments
The following solutions will address print or part-related causes of the defects. Choose among the suggested actions below and select the best approach for your application. Usually only one type of adjustment is needed.
If problems persist, please reach out to Carbon Support.
Explanation & Causes
Explanation
Suction forces pulling down on the part are stronger than the adhesion of the part on the platform.
During normal printing, the suction forces and part adhesion are in balance. Under-adhesion occurs when either the suction forces are higher than normal or adhesion has been decreased.
Reference DLS Printer Dynamics for more information on suction forces.
Causes
Print Preparation or Part Design
How the part is oriented, supported, or designed is causing the defect.
Root Issue | Problem | Why Defect Presents |
|---|---|---|
Base cross section | Missing first slice | A blank slice presents at the beginning of the print, restricting adhesion. |
| Flat base not snapped to platform | The part is rotated slightly such that the platform cross section is too small to maintain adhesion. |
| Undercut | When only a few slices have been cured, an undercut (filleted or beveled edge) can use suction forces to peel the cured slices off the platform. EPU, FPU, and UMA are especially susceptible. |
| Small to large cross section later in the print | Suction forces increase later in the print from large cross sections and the base cross section is not strong enough to overcome the force increase. |
| Asymmetrically oriented part | Suction forces can cause torque on asymmetrically orientated parts, rotating them off the platform. |
Unvented volume | | A vacuum in an unvented cavity exacerbates suction forces. |
Hardware
The printer, cassette, or platform is dirty or requires maintenance to resolve the defect.
Occasionally, a defect may indicate the printer requires servicing by a Carbon engineer.
Root Issue | Problem | Why Defect Presents |
|---|---|---|
Cleaning | Dirty platform | Part cannot properly adhere to the platform if pre-existing resin is present. |
| Dirty cassette window | An improperly cleaned window can hinder the UV light required to cure the resin, reducing adhesion. |
Misalignment | Improper seating | Platforms and cassettes may not seat properly if dirty or incorrectly installed, causing base slices to not fully adhere. |
| Unlubricated kinematic pin mounts M1/M2 Printers only | Unlubricated kinematic pin mounts are sticky, causing hardware to be misaligned. Misaligned hardware causes base slices to not fully adhere. |
Resin
The printing material is expired, beyond the printing range in its pot-life, or has been improperly mixed, causing abnormalities in the print.
Root Issue | Problem | Why Defect Presents |
|---|---|---|
Expired | | Resin does not cure properly at the base, reducing adhesion. |
Past pot-life | | |
Mixing | One-part resin not mixed | Pigment must be fully distributed in resin to cure properly at the base for full adhesion. |
Print Plan Adjustments
Print Plan Adjustments adjust the print plan to optimize mid to high volume production and/or address part defects.
In doing so, adjustment may both prevent or cause defects. Below are adjustments that can cause this defect.
Printing Stage | Parameter Type | Type of Adjustment | Why Defect Presents |
|---|---|---|---|
1 Pump Up | Platform Speed | Increase | Increased Motor Up Speed increases suction forces |
4 Settle Down | Delay Timing | Decrease | For EPU Pros only, less delay time before exposure can impact adhesion when less heat has saturated the platform and resin |
5 Exposure | Exposure Timing | Decrease | Adhesion is decreased with less UV exposure |
5 Exposure | Brightlining | Decrease | Adhesion is decreased with less UV exposure |