Update: 17 Jun. I have update "mini spool d2 p1 r1" to r2. The r1 update was too hard to insert into the mini spool so I adjusted it.

Using 250g spools in the ACE pro requires the use of adapters. However these adapters do not work 100% properly when printing multi colors and the ACE pro is switching between spools. The process of switching requires retracting the spools and in many cases the retracted filament will jump into the space between the small spool and the adapter causing filament entanglement. To solve all these problems I made the following modifications:

1) I have modified the mini spool adaptor (designed by: piodeer (@Naoh_2641270) by adding a ring on the insides of the adaptor to seal the gap (in r0 I made the ring a bit higher).

2) In r1 I added a support behind four of the fins in the male part of the adaptors (see picture) to give some strength to the fins and help prevent the small spool form slipping. (In r2 I adjusted the gap to make it easier to insert the mini spool).

3) Designed a filament guide that needs to be installed on the inside of the ACE pro cover (no tools require very simple installation). See attached pictures (this part was not changed as part of r1 revisions so it is still labeled r6).

I recommend printing the adaptor and the filament guide using PETG or ABS since the ACE pro is also a dryer and the temperature inside the ACE Pro would warp PLA. You can print the mini spool adapter with PLA and see if it holds its shape but definitely the filament guide must be printed in PETG or ABS. Print the filament guide as you see in the pictures to avoid the need for support. I have updated the design of the adapters to r2 which should solve the small spools slippage problem and also make it easier to insert into the mini spool.