To further increase the credibility of the concept we wish to start the semester by drilling in a prostate.

To do this we need permission from Sebastian, Øystein needs vaccinations, and the prototype must be ready for it.

Normal Clamping instead:

We decided to revert back to normal clamping for the prostate test. The progress is described here.

First a 4mm thick aluminum plate was cut using an automated plate cutter. Then it was mounted to the aluminum extrusion profile that came with the CNC mill using some nuts and bolts. After that, some mounting holes for the clamping rods used in the MRCL prototype was drilled and tapped, before some spacers were produced. Everything was then put together. The almost finished prototype is shown here, and is ready to be mounted onto the CNC. The only thing remaining is to carve out a toolpath for the mill to follow. This has to be done when pictures of the prostate that we are going to mill out samples from are acquired.

Finishing the prototype: Done

The collett nut: Fixed

The collett nut turned out not crooked after all. We simply installed it wrong. To install it right one first snaps the collet into the nut and then insert it into the CNC. Only then can you insert the mill bit and tighten.

Filtering the suction: Fixed

Before testing can commence some improvements must be done to the prototype. We have to make sure that the sanitation aspect of the prototype is of high enough quality.

Our primary idea is to design a filter adapter for to attach to the tube sucking air out of the vacuum. This would stop biohazard material from entering the vacuum causing further contaminations.

If this was to work as intended, we would be ready for testing. 

Our assessment of the filter requirements are as follows:

 The particle size should not differ much from the spoon created by milling other materials. 

 "THE MEASUREMENT AND DISTRIBUTION OF WOOD DUST" says that wood dust diameter is normally in the range 30 µm to 10 µm, but with thin processing can be as small as 5 µm.

The difference is that we would now be handling biohazardous material, which is more dangerous than wood dust, so the safety margin for how much dust should be allowed to pass is probably not strict enough. This we must research further.

We will probably need to learn what the industry standard filter for prostate tissue is, as that is what we will need for the final prototype. 

We were advised to look into the filters sold by vwr. We also got a vacushield filter to test on our current setup. 

The setup he proposed was a multifilter solution.

 - First a filter placed early in the system, meant for the biggest chunks of tissue. The purpose of this filter would be to share the load of the microfilter so that the microfilter would clog so fast. 

The vacushield did not work with the vacuum at all. The air flow was reduced from 12-13 m/s to 0,6 m/s, which was far from sufficient for securing a slice to the base plate.

We followed the advise and looked into HEPA filters at vwr. Here we found two types:
 - https://no.vwr.com/store/product/556056/luftefiltere-hepa-venttm-og-hepa-captm-whatmantm

 - https://no.vwr.com/store/product/36147974/disk-filters-hepa-vent-whatmantm

They have more promising specs in terms of volumetric flow and maximum pressure, but whether they will be good enough is still unsure.

The last idea we have regarding a filter is a very big filter that, is effective against microorganisms, while still providing a valid airflow.

Sample Extraction: Fixed

As the popping extraction solution is still unsure, we have devised a different way of extracting a sample for this one test. 

We will machine out a 2mm thick square in our base plate so that our mill can mill below base level in following that square. This will not be a permanent solution, but it will work in the sense of proving successful prostate milling. 

Sebastian

Sebastian will try to get the permissions. 

As extra safety measures the test should be conducted down at the MR Core Labs and be performed by one of the scientists there. 

Getting permission to make a sample is much easier if they have a specific sample of a complex shape that they want milled out, and we can guarantee that we will get it out. 

The test

Nothing have been written here yet.

The results

Nothing have been written here yet.