How can you compare prices for custom PDMS microfluidic chip fabrication?

0.5 MPa is not particularly high for a PDMS-glass bonded chip, but the key lies in the bonding interface. After plasma bonding, if no post-treatment is performed, the bond is prone to delamination when exposed to water vapor or repeated pressurization. It is recommended that you perform a pressure-holding test after receiving the product: pressurize with water or air to 0.5 MPa, close the valve and hold for 30 min, and check for leakage, seepage, or channel deformation. If it is used for cell or droplet experiments, it is best to cycle the pressure 10 times and then retest. You can require the manufacturer to perform 100% airtightness testing or pressure resistance sampling inspection before shipment, and ask whether they anneal after bonding. The glass thickness should also be confirmed; if it is too thin, it is prone to cracking under a high-pressure fixture. It is better to spend a little more to choose a manufacturer with pressure resistance reports and warranty.

The difference between 80 and 300 per piece usually comes from several points: first, whether there is a first-article full inspection and dimensional sampling report; second, whether high-temperature heat treatment or solvent-assisted bonding is used after bonding to improve strength; third, the thickness and flatness of the glass substrate; fourth, the cleanroom class and packaging. For 50 μm channels, it is recommended to require the manufacturer to provide SEM or microscope-measured channel width and depth, with tolerances preferably controlled within ±5 μm. Bonding strength can be evaluated using tensile testing machine or pressure resistance test reports, not just appearance. For a small batch of 20 pieces, you can require each piece to be numbered, randomly sample 3 pieces for dimensional and pressure resistance verification, and use the rest for experiments. If the cheap ones fail sampling inspection, subsequent batches may be even more unstable.

For 20 pieces of PDMS-glass chips, a reasonable prototyping lead time is generally 2-3 weeks, including CAD confirmation, mask fabrication, photolithography, bonding, and quality inspection. If urgent, some manufacturers can do it in 1 week, but this usually incurs a rush fee and carries significant quality control risks. It is recommended to first produce 3-5 pieces as a first article, and only place the order for the remaining quantity after receiving them and testing the dimensions and pressure resistance. Do not have the entire order made all at once. When requesting a quote, ask clearly whether the photolithography mask fee and first article verification are included; some low quotes spread the mask fee into later volume production. In addition, if you have subsequent volume demand, you can ask the manufacturer to provide batch-to-batch reproducibility data, such as the CV value of channel width across different batches, which is quite critical for experimental stability.